The P3 seems inordinately expensive compared to other similar items on the market, e.g. the Sigelei 50W, 100W, 150W box mods. If you're looking for the tube form factor, the VAMO is quite a lot cheaper and does exactly the same thing. I am no longer able to justify US$250 on a regulated mod when there are others that are far superior and cost US$90. I'd suggest looking into the world of box mods.
Back from the tangent... As for tanks, Aspire's Nautilus series and Atlantis are my personal recommendations. In my limited experience with these, my personal favourite was the Atlantis, which is also the most expensive by far (still less expensive than anything Provari seems to make).
Please do more research before you make such an investment. I'd hate to see you throw several hundred quid down the drain like that.