This is the first EDGE upgrade I've seen by T-mobile. It was sorely needed, the GPRS cell was partially overlapped by the HSPA+ network in Lafayette, LA. Broussard's cells are the only T-mobile cells around I'd consider congested. Most south of town are still GPRS, but the one downtown just went to EDGE sometime this month. It makes sense considering the HSPA+ from neighboring cells.
Gosh, Broussard's in the news? Next thing you know, it'll be Youngsville, or...or..Pecan Island?
In situations like that, I think T-Mobile is mainly testing if the network in an area is capable of running something higher. That's how it was when 3G launched here in Mobile, AL; for about a week straight, my TM506 would keep switching from EDGE to 3G, which was killing my battery.
Once everything settled down, everything was wonderful, though, I didn't get to really try out 3G until I bought my Exhibit II (wasn't going to switch to a prepaid w/ data plan on the TM506).
My town is still on one Edge Tower and one GPRS tower.. Always switching off and on them.
It's now 3G all the way down to new Iberia and there is Edge, it's weird though where I'm at I had three or four bars of 3G and my iPhone is dropping service. Also they don't seem to have back haul in place because edge is just as fast download wise. The upload is .4mbps though.