In VV, for a good price point, excellent ruggedness and performance (good voltage regulation [no drift as batteries discharge], good run time between charges, 15W max power), notcigs Infinity Pro. Slightly more expensive, same electronics and run time, Buzz Pro. Lower cost, lower build quality, provides an LCD display (if you want one, different people have different wants), Lava Tube (or one of the many ones popping up now that are actually the same unit, just rebranded). Higher price than notcigs, also excellent per many users, a bit lower max watts though higher max voltage than the notcigs PVs, has an LCD, the Provari. These are all tube mods, there are also several good box format ones out there, and Reo is coming out with a new one based on the notcigs circuitry.