The ProTank II was a real piece of garbage when I got it, either it gave dry hits or it leaked, flooded and shot liquid into your mouth. Then I saw RiP Tripper's video about the micro coil with cotton, boiled up some, screamed "Geronimo!" and disassembled my 1.8Ω head.
All I did was replace all the silica with cotton while retaining the stock coil, and now it vapes like a champ with great wicking and an even greater flavor. They should sell those as RBAs, not as clearomizers. IMHO.
The eGo-CC on the other hand doesn't leak, flood, gurgle nor give dry hits at all, and it puts out a serious amount of vapor with crisp flavor even with the SR 2.2Ω head on a 3.3V eGo battery.
It has a really great, clean atomizer flavor, but it tastes like a dripping atomizer that ran a bit dry and needs some drops most of the time. Blowing lightly into the mouthpiece a couple of times fixes that for the next couple of hits. It's not dry nor scratchy, but it could use a little more juice to add more flavor.
The window seems to be a Polysterene. It is clear, but if you look inside an empty tank, you see those rainbow shadings like on a CD jewel case where the plastic is covered by the metal. I've experimented a bit with clear plastics, and you can leave a drop of Radiator Pluid on a jewel case as long as you want, Polystyrene doesn't melt nor frost. If they've used Polystyrene for the eGo-CC, then neither should it melt or frost, either.
The only bad thing about it is that the windows don't line up with the logo, and neither line up with the button, unless you screw everything together loosely like on the photo above. The finish doesn't match the Joyetech eGo batteries, either. You also need a needle cap bottle or syringe to fill it. Oh, a 5-pack of the heads is $25, it comes with only one 2.2Ω head in the box and no spare 1.7Ω low resistance head to try out.
It is definitively a nicer out-of-the-box experience vs. the ProTank II. And
replacing the "flavor wick" with SS mesh for more flavor should make this a legitimate option for light vaping on the go.
Edit: A
rebuildable atomizer head actually exists, if you care to order it from Romania.