On almost every F2P game that I've tried, I dropped at least $10 at some point just to see if the stuff you can pay for is actually worth it, so I'm going to review them first from the sole perspective of F2P only, then add in a section at the end about the paid experience. I figure I'll start off with a couple of unknowns, so here it goes:
Shaiya
As F2P: Shaiya is one of the offerings by F2P juggernaut Aeria Games. It bills itself as a "fantasy MMO" in the vein of Everquest and seems to take it extremely literally as it's nearly identical to EQ1 with updated graphics. It features the now typical curve of MMO leveling involving quest chains that have you killing rats and the like for an existent but instantly forgettable storyline while moving from town to town. The unique bit about Shaiya is that it has different modes: Easy/Medium/Hard/Ultimate. The harder the difficulty, the more XP it takes to level up, but you also get access to rare items (you can't really use ANYTHING you'd find in a dungeon in Easy mode), a higher level cap, and more stat/talent points. Ultimate mode is similar Hardcore mode in Diablo, where if you die and a buddy isn't right next to you to rez, that's it, character deleted. The problem is that if you're new and create a character in a lower mode, you'll find you hit the ceiling pretty quickly, and you're forced to play at least through normal to unlock hard and hard to unlock ultimate, not even paying can get you through that cycle, so it takes a really long time to get through.
There are 6 classes (technically 12, but they're copy/pasted across factions) and 4 races, 2 in each faction. Humans and Elves are the goodies, Nordein (dark humans) and Vail (Dark Elves) are the bad guys...such innovation there.
The game has a crafting system and PvP, but the former is really not viable without buying stuff from the shop, as it allows you to make more, better stuff (more on that later). PvP, though, is actually quite fun. Each class has their own role, and the battles take place largely in an "Alterac Valley"-esque scenario of territory control along a linear pathway with NPC support on both sides. The bad news is that you can drop items in PvP, although it's only a random chance until a certain level, so don't suck. PvP is honestly the most enjoyable part of the game.
The real question, though is simply: "Is it fun?" To which I would answer "Not really." If you've ever played Everquest or even World of Warcraft, Aion, or any other current gen MMO, this will seem like a crappy knock off of that. The graphics are only slightly better than EQ 1, a game which came out in 1999, and the gameplay and interface, which have evolved in subsequent titles, are very close to it.
If you Pay: If you decide to buy stuff from Shaiya's item mall, you'll find the standard assortment of F2P mmo junk like transfers, appearance, race, gender, etc changes. They also have useful items like prevention of item drop for X amount of time. No problems with that, but they do commit the CARDINAL SIN of F2P gaming by selling power. They sell crafting items that boost the stats of stuff you make, and more powerful versions items that can be obtained very rarely in-game that increase stats on an item you already have. This means that to get the best quality character, you'll need to buy those stones and play in Ultimate mode, which is ridiculously difficult.
Bottom Line:
If you've never played an MMO or find them insanely fun, but can't afford your EQ2 or WoW subscription, I'd still pass on this, because there are far superior titles out there that do what Shaiya does better, and I'll name a few of them later in this series (if I ever decided to keep it up.) The F2P is extensive, but the fact that they sell power and modes require forever to work out means it's hardly worth it.
Atlantica Online
Atlantica Online is produced by Korean company nDoors who also makes a bunch of crappy online casual games that are big in Korea and nowhere else. From what I'm seeing as I'm doing some research on it (it's been ~2-3 years since I actually played it for any length of time) it's apparently pretty big in Korea and considering the first Google hit is in Spanish, probably in Latin America or Spain as well.
This one bills itself as a Strategy MMO and is currently the only game I've played that has successfully pulled this off. Battles take place on a 3x3 grid with you and your opponents on different sides, and skills are used in a turn based format (with an enforced time limit in PvP). Each skill has different effects and a different targeting range, plus positioning determines how much damage someone takes (and if they can take it at all in melee), so both positioning and group composition are very important to the game. You build your squad by hiring and upgrading Mercenaries, and different classes become available in different places at different levels and at different costs.
The number of possible classes is massive, thus making the different possible group combinations incalculable (without a calculator or a few minutes of scratchwork, but it's more trouble than it's worth and a really, really big number). They all fall into categories based on their weapons, but each has individual special abilities.
What's an MMO without loot, though? It comes in various forms, but the best stuff you'll often get in treasure boxes that vary depending on where you are when they dropped. You get treasure boxes for completing quests as well, but all the rewards are always random, which can lead to a lot of grinding if you want to get something more specific. A lot of dungeons feature timed quests to find specific items or defeat specific enemies, so sometimes it's in your best interest to avoid fighting as much as possible. The Overworld map shows where enemies are, and you can usually run around them unless you get pinned in or face some types of monsters that move more quickly than you do. Overall, I really like the combat/dungeon system, but the loot system could use some work, as it tends to overgear some of your party and leave some others far behind. There is a way to upgrade gear to the next tier, but it's prohibitively expensive to do it for more than a few items per tier.
The big problem comes with the leveling system. The curve is way off. Once you hit certain points in the game, you have to grind enemies and dungeon runs repeatedly for gear and experience, even if you've completed the quests and slain the big baddie of the area. Or, sometimes, you'll finish one area, arrive at the next, and find the quests are either locked to your level or far too difficult to complete without farming for more gear/exp. Not to mention if you want to fill out your party at the level you unlock the slots, you will have to farm a lot of money from the area. It's this amount of grinding which is one of the few shortfalls of the game and might cause you to become bored with it for extended periods of time. Also, trying to keep all your mercs on the same upgrade level is next to impossible thanks to the cost.
PvP, as I said, features the same turn based combat with time limits on turns, so you have to be pretty quick. There's a ranking system and a few rewards, but it's not a huge deal. You can group with other people and fight alongside them (the battlefield has room for multiple 3x3 squares across each side, but it limits you to fighting the one in front of you and directly to its left and right) in PvE dungeons and there is a form of raid content. There is more than enough content for you if you just want to go it alone, however, at least until the very end game which can take months to get to without paying for lots of XP boosts and the like.
If you Pay:
You can get a lot of treasure boxes (that are otherwise obtainable in-game), temporary stat/exp boosting scrolls (some of which are available in-game, but more powerful versions are on the store), and some exclusive cosmetic stuff, like rare mounts. There are also very good convenience items like licenses that let you use the Auto-battle function (which is actually decently well done as long as stuff you're fighting is below your level), teleportation between major cities/areas, and the like, but all of that is tradeble and can be acquired on the auction house, albeit for sometimes large sums. They don't break the cardinal rule, but it might be worth it to shell out a few bucks to grease the wheels when you get into a level where you're stuck.
Bottom Line:
I think a lot of people who would actually read a thread with this title on this forum would derive a lot of enjoyment from this game. You probably wouldn't spend a whole lot of money on it, and you may quit and come back every couple of months, but it's a great free alternative to the big AAA or even larger indie titles out there. There's good quality here, but you will have to put up with the grind mentality that MMOs force on to you, so if you absolutely HATE that, you might want to look elsewhere.
That's it for today. Rate it, comment on it, I might do more and/or download some more games to review if you like it. If I missed certain facets you wanna hear about, say that too and I'll try to be a bit more thorough, this is really my first shot at this kinda thing.