I think the Vamo is a close second behind the MVP, if only that you don't have the additional expense of batteries and a charger with the MVP. That said, the Vamo offers a better range in voltage/wattage and is not a box mod (if that turns you off). For toppers, I like the aerotanks (even the version 1): you can get a range of resistance heads for them (and even modify single coil heads to use in them), they hold a fair amount of liquid, and they are glass (or steel if you get the Mega/Mini/v2. YMMV, but I'm very happy with the combos.