Well, maybe I'll have to start playing with the virtual one on the epic to get use to it.I've seen 16M/5m+ on LTE here in Austin, so YES, it's worth it. I think the physical keyboard is going the way of the dodo bird. Even my Daughter who almost always insisted on the Physical Keyboard has gotten used to her Evo 4G LTE with just virtual keyboards. I love my S3 and the Kii keyboard (or Swype, or Swiftkey Flow).
Yes, any new 4G is LTE, so you'll need a new phone to get 4G speeds.