Ok I just switched from Verizon to T-Mobile today. Hello unlimited 3G+!!! the fastest I've seen on my phone is 3 mbps down, which is sufficient for just about everything.
In the area where I get 3mbps down a T-Mobile branded handset got 4mbps. It's probably a slight radio difference and i'll update this when I have full hspa+ service and see what kind of download speeds I can get with my Verizon branded phone.
Lastly, I didn't have to punch in any apn settings for messaging to work, it just worked with no problems at all.
As a bonus you still get data sense to keep track of your data if you are interested, but you can't get any of the t-mobile exclusive apps
If you have questions PM me, I'll try and respond quickly but I can't guarantee that.