Is the iPhone 4S compatible with T-Mobile's 3G network?

I need to know a couple things regarding T-Mobile's wireless coverage:

1.) Have they yet completely farmed their 3G network coverage?
2.) Have they completely rolled out their 4G HSPA+ network coverage?

3.) How's their coverage in the midwest (specifically Illinois/Chicagoland area)?

I used this website as a general guideline, but I'm still not sure how accurate that map is. I'm not even sure if that map includes data coverage or if it only showcases their voice/text coverage:

http://www.t-mobile.com/...e/pcc.aspx

Additional questions regarding T-Mobile:

4.) Can the iPhone 4S tap into T-Mobile's 3G network? Or would I be stuck with their 2G edge (even though they're refarming 3G/4G)?

5.) Are there any carriers that offer an iPhone 4S that is compatible with T-Mobile's 3G network? In other words, if I want to purchase an iPhone 4S to use on T-Mobile's 3G network (assuming I even can), can I get a phone from another carrier (for cheaper) and then unlock it at T-Mobile, or do I have no choice but to buy a factory unlocked device?

If anyone can answer any of these questions even partially, it would help a great deal. Thank in advanced, guys.

Look not compatible with 3g only with 4g http://9to5mac.com/...00-vs-att/