In terms of 3g speeds (due to hspa+), and phone flexibility yes, but GSM really falls behind CDMA indoors.
My wife had at&t and couldn't talk indoors more than 10 feet away from a door or Window. Didn't work very well at work either but when she switched to Verizon, she gets a very strong signal in both places.
CDMA = GSM
they have different pros and cons