I have a 3G AT&T iPad now.. Never really had any data issues with it.
Got my iPhone 4 little less than a month ago (for work) on Verizon network. Yet to have a dropped call or data issues. I currently have over 400 minutes talk time. About 80 emails a day via 3 push accounts, facebook notifications, google sync, ect.
Now my iPhone naturally gets more 3G data time then the iPad. iPhone ispn me 24/7. iPad is never carried away with me unless I think I need it..
But in reality, how bad IS AT&T service data wise? Everyone complains of dropped calls, and a little of a clogged network (San Fran, NYC) but for everyone else..??
I'm tossed who I want to go with for my iPad 2. I'll be picking up a 16gb 3G again (I have 8gb free on this one now).