The Phone:
The phone is OK, nothing particularly special. Most of what I need is available, although the music player is rather annoying because shuffle seems to be limited to only a section of my music library (on MicroSD card, many many songs).
Other than that, since there are no very particular apps I used to use on my Android phone, there's no major miss-out. The only thing I would miss is I had a nice offline Mahjong game (as in, the proper game, not tile matching crap) which isn't on Windows Phone, so that kinda sucks.
Battery life is about ht esame (where I am) as my S3 was getting, which is annoying, but my S3 seemed to tank because (I assume) of mobile signals here, as when I went abroad or was in the UK it was fine and would last a lot longer. I hope that's the same for the Lumia 640.
I haven't had a chance to try the Lumia 4G speeds (no mobile networks support it here) or dual SIM (as I haven't got a second SIM at the moment but expect to when I go back to the UK hopefully from July).
Haven't found much use for Cortana on the phone itself yet, other than a slightly easier way to set a one time alarm.
The Band:
The band is not the most stylish or comfortable thing in the world, but you get used to it. First few days were pretty awful, but it's getting better/less noticeable now. I did come from having not worn a watch for something like 5 years so that doesn't help (or maybe does?)
It's not waterproof, but I take it off when I shower and use that as charging time. So far I haven't had to recharge it outside that, so I've been wearing it 24/7 for a week or so now apart from during showers, but then I haven't really done much GPS/exercise use other than 15mins or so cycling to/from work (in total).
It gets a GPS lock pretty quickly, which is nice, and heart rate monitoring seems reasonably consistent (my daily HR is consistent day to day and my sleeping HR is significantly lower than during the day and day to day).
I went for a ride using the band and with an older HTC Android phone I use for ride/GPS tracking, and they were basically 100% matched in terms of distance tracked, so I assume the GPS is at least as accurate as a somewhat older phone.
Cortana could be fun to use when Windows 10 for desktop/laptop supports it. I have used it to play tracks on the phone and to set alarms, but that's about it so far (you can use your band as your Cortana voice receiver and then it gets the phone to do the behind the scenes work).
If you could command your PC using Cortana from a Band that would be cool (e.g. while in a different room).
I think if I did more exercise it would test the battery out a bit more, and provide more benefit as well, but I haven't had time and I've been lazy as well. I haven't use it in watch mode (display always on) so that also massively helps the battery. I'm at my computer at work so I don't need a watch clock.
Not sure how accurate the step counter is on the band, but either I spend way too much time in my office wandering around, or it's "over counting" steps somehow.
The Other:
Since Microsoft Health can be linked to some other websites (e.g. for exercise tracking, food tracking etc), I've managed to keep a diary of my food for the last 10 days or so.
I'm trying to lose weight anyway so was thinking I mostly had a low-cal diet, which I kinda did, but it was a "5 days eating not much in the week then have a bit more at weekends" type diet.
After tracking my weekend eating, I realised it was a "5 days of not much and then make up for that entire 5 days at the weekend" sort of thing, where I consumed nearly as much in 2 weekend days as in the entire rest of the week, so now I've fixed that, which will help.
Having the band has provided a bit more motivation for recording my diet, at least for the last week, which is one benefit, and also in determining the mix of what I eat (carbs/fat/protein etc) and working out that I could do with adjusting it to get some more protein.
It's not a direct Band thing, but I'm doing it because of the band, and then the food recording site (myfitnesspal) also pulls the info from the Band when you record exercise (although I think it does it at the end of the day) so you can see "net" calories i.e. after any exercise.
End Blog.