Instead, I found myself slowly realizing the servers had more in common than they ever had differences. Due to the matchmaking service, I found myself battling against equally skilled opponents, no more and no less on each server. There were long sessions where the experience on each server blended into one another, where I thought I was playing on Asia until I realized I was actually playing on US (no wonder everyone spoke English so well).
At the beginning, the general play style of each server had distinctive themes, but as time passed strategies and build orders converged. I generally saw many one-base all-in builds from Asia, but eventually started seeing those in US and EU as well. I saw a Protoss 2-gate opening and Terran 1/1/1 build that spread like wildfire on all servers. The easy accessibility of replays and VODs means that there is no true isolation of strategy anymore.
As for player skill, as I mentioned, I was matched with equally-skilled opponents no matter what server I played on. I made top five Diamond on all three servers, and my point rating and win/loss ratio were similar. That said, I have no idea what players are doing above or below my skill level. It's likely that top players play far differently than we do. As for lower-tiered players, I saw some weird, cheesy tactics during placement matches on all three servers. I also wanted to point out that I was probably occasionally matched with other cross-server players from the US due to good ping, but most of the players I met were definitely overseas.
Overall, I had a lot of fun and met a varied, diverse set of players from many different places. It turns out Starcraft players have far more in common than we have differences, and any differences are far greater within a server than between them. I will certainly miss this experience when retail hits the shelves, and I think without cross-realm play the game is missing on something special.