You can get Verizon reception with a Sprint phone. PRL is an acronym for preferred roaming list, it is the list of carriers and cell towers that will allow you to roam on.
Having a VZW prl will allow you to roam on a strictly Verizon system and receive the full benefits like you were a Verizon customer.
I'm pretty sure I got that just about right.

Please someone let me know if I'm off the mark.