I live in southern NJ and have been pretty impressed with AT&T's 4G LTE coverage in my area (iPhone 5, it probably would be a Galaxy 4 if it had LTE). Cherry Hill, Deptford, Moorestown, Marlton, Berlin, all have LTE coverage. I recently went to the Microsoft Store in Newark Delaware with a friend to get a Surface RT, sure enough LTE coverage down there as well.
As far as speed goes; I pulled 55 Mbps down in Cherry Hill, but I generally see LTE speeds between 10-30 Mbps. I could have switched to verizon, but forcing single customers into a share plan for over $100/month was a big red flag from big red.
AT&T customer service has been decent enough as well. I missed a bill payment once and didn't realize so they stopped my service. Customer service waived the re-activation fee without hassle and had me re-connected quickly. Other than that I've never really had to call them.
I'm not a huge fan of AT&T, but in NJ they seem to be the best choice at the moment from a price/performance standpoint for a single customer. Also, I'm still grandfathered on the Unlimited/5GB $30 data plan.