I am an AT&T rep here in WV, I was having issues with the device as well.  I switched from the Galaxy S II (HSPA) to this one and was disappointed with the performance. 

Data was slow, device was working slow and the battery was dying quickly.  The resolution?  Remove the AT&T Mark the Spot app from the device and see if that helps the issues you may be having.  The performance on the device has improved tremendously since removing this application.

Please let me know if that helps, thanks.