I remember about a year or two ago when 3G was 3Mb here in the Phoenix area there were rumors of getting faster speeds by upgrading to hsdpa+ but they must have never done the upgrade due to the impending AT&T buyout since the speed is still only 3Mb in downtown Phoenix. However since I'm on the East side I can't even get that, just Edge. I've tried setting it to force WCDMA mode but that doesn't work and it just defaults back to Edge so none of the Android apps will work unless I use wi-fi.
Actually they do have HSPA+ in the area and my old Blackberry still gets 3G on it but that's not an option for my new Samsung "4G" Android phone. It only has WCDMA for "4G" and GSM for Edge with nothing in between. As far as I can tell from looking at the Samsung phones in the store none of them can get 3G so if you don't have 4GB available they don't work at all except on Edge. The coverage map shows good coverage over the whole Phoenix area but it's just Edge and 3G.