So I finally did it and went from my old Blackberry to the iphone 5 on T-mobile. So far I can say that there are a bunch of things that I really like - and a bunch of others (and i knew that) not so much, like the way the mail application works and the fact that it has a touch screen for typing. Oh, well. The other thing I had to leave behind is my decade old plan including (true) unlimited data. Not that I used a lot of it but I never had to watch it. Now I only get the 500MB at high(er) speed rates and then it drops to whatever. So I've actually watching it over the last two days and I already racked up 100MB. Probably from initially setting up things at the office without wifi turned on, etc. But I'm still a bit puzzled how the iPhone 5 and/or T-mobile handle the data priorities. I've been on my own wifi network since Friday evening and it looks as if I'm still adding data to the plan. The phone shows "T-Mobile" on the left and a wifi signal on the right. Under "general" I turned now off "cellular". What if I don't do that? Will it prioritize my wifi network and not use the "4g" coverage then? Is there another way to set that up? Are there shortcuts or "profiles" for these settings?