Is there really any differences between these two other than minor cosmetics and provider? I'm just curious which people think is better and reasons why.

All 7100s are internally the same. Only the shells are different. Different size, key shape and spacing. I don't think Cingular includes the IM software that T-Mobile does, but I am not an IM user, and I am not 100% certain (answering your other post).

Beyond that, it comes down to carrier coverage and prices.

personally i like the 7100g shell a lot more than the 7100t

one of the actual bigger differences is that the 7100g has raised keys (like all other BBerrys) unlike the 7100t's flat keys and they are also spaced apart more...making it easier to type.

Cingular has the best GSM coverage and costs more.
T-Mobile has rotten GSM coverage but the service is cheap.