Unlocked iPhone 5: Switching carriers

I've been looking into buying an unlocked iPhone 5 and am a bit confused as to what the possibilities are with each model.

  1. I'm currently on Verizon and have read their version of the iPhone 5 is unlocked. Being a CDMA carrier, is this only transferable to Sprint or are AT&T / T-Mobile options as well? Based on the tech specs on Apple's site, it seems it has many of the bands/frequencies the other models do as well.
  2. In terms of LTE, what is the carrier compatibility?
  3. Are any of the iPhones capable of running on both CDMA and GSM networks?
Any insight would be much appreciated.