I have three Protank 2s, and an Anyvape Davide BDC. The Protanks are solid, but they're also fairly high maintenance. The coils don't seem to go through quality control at all, so some of them fire better than others, and some are just plain leaky. You'll possibly find the same with Mini protanks, EVODs, and anything else that uses kanger single-coil heads, but if you can put up with wiping off the battery contact every time you refill the tank then they give good flavour and vapour.
The Davide can use the Protank single-coils, but is meant to be used with the Aspire dual-coil heads, which don't leak nearly as much, and give better vapour production, but they go through the juice fairly quickly.
If you prefer top-coil tanks then the Vivi Nova is pretty decent, though again I found it to be quite high-maintenance. If you want to go for a dual coil option, then Smoktech make a dual-coil version called the X2, which has better seals and doesn't require as much attention.