The MVP2 is a great mod. Large battery capacity, variable wattage, ego and 510 threads, micro usb charging, relatively compact form, low price, good build quality.
It is box shaped though, which some folks don't much care for. In that case, the VV v3 is a good alternative. It is a thinner, ego-shaped version of the MVP2. Smaller battery, smaller size, smaller price, all other features are identical.
I'm not too familiar with tanks, but I have bought the Mini Protank III as gifts for people and they all like them.