Yeah, sorry I didn't get past the data plan page (and it was the first one I skipped to). First off, how old is this article? Verizon just got rid of their unlimited data plans, they are now tiered similar to AT&T (although their minimum plan is now $30, bad starting point).
T-Mobile is also offering different plans for different usages. I think they have a new $10 data plan (2GB or something like that), maybe they stopped that promotion. I currently get "unlimited" for $30/month, which was an add-on to my Family plan ($59.99/mo 750 minutes + $10 per additional line).
Finally, like others have said, GSM supports simultaneous talk and web. I downloaded an MP3 the other day while talking to my manager. I think you need to have 3G or HSPA+ (a restriction even AT&T would have) since I think EDGE and the phone call use the same frequency band.
Also, did phone selection criteria take into consideration the fact that AT&T has locked all but 6 of their android phones from installing third-party apps? And of those 6, I'm not sure you can install any third-party apps other than the Amazon App Store. So yeah, I'm not really sure I'd consider any of AT&T's Android offerings as true offerings.
Maybe this article should have been based on actual research, and not just what the commercials are saying.