I currently use a V2 ecig which is a 808 4.2v. But I was interested in a 510 of some sorts, perhaps the provari. What are some other good opitions for me to try?
That depends on why you want it. Are you going to be comfortable carrying around such a large battery? Do you want it for around the house? Variable voltage opens up a world of possibilities.
Variable voltage is good but it can also limit a person on what type of hardware they can use. Both the ProVari, BuzzPro (not as bad), and Lavatube (horrible) will limit use of dcc's. My favorite vape is 6V with a 1.6ohm dcc....I can't use any of the 3 mods that I listed. However, Krimson Kustoms builds a VV box mod that allows this.