The "Big Three" (or Four, actually) are the ProVari V2 or the Darwin (both single-battery boost VVs) and the BuzzPro/iPro (stacked two-battery buck VVs). Each has pros and cons, each has a justifiably large fan base, and any of them would almost certainly satisfy your wishes.
(By the way, a ProVari V1 is probably not what you need---the 2.5 amp limit won't allow vaping low-resistance dual coils at high voltage, as you may already know. The V2 has a higher 3.5 amp limit.)
I don't own either a ProVari or Darwin, but I have both the BuzzPro and iPro, and I like 'em a ton.