I picked up an MVP at my local and got one of these at the same time - I probably would have passed it up if not for getting it on the cheap due to my other purchases. I'm really glad that I decided to try it out. Generally speaking I prefer glass over polycarbonate, and in many ways it's kind of like a weird Protank/Vivi hybrid, at a glance nothing that special about it. I'm not even 100% clear on what the spring loaded plunger system does, or if it even has any real benefit.
There is, however, two tiny design details that make this tank awesome. First, when you remove the drip tip, you'll see a small machined groove for the drop tip o-ring to seat into. This means that the drip tip is really firmly attached and perfectly sealed. A tiny detail, but let's face it loose tips suck. The second detail is killer though, and also related to the drip tip interface. When you remove the drip tip on the Unitank, you will find that the little condensate collection area is conical or funnel shaped (whereas every other tank I've ever seen this is flat). This means that after a bunch of vaping, there isn't any liquid pooled here for you to suck up into your mouth. It all just flows back into the tank. Based on the way the parts fit together, it looks like this liquid gets diverted into the top section of the tank and not into the airflow/atomizer tube, which is brilliant.
So even though this isn't the best or most revolutionary tank out there, it has some pretty great little details. The system for handling condensate is fantastic and on its own makes this worth a look IMO.
Dear Kanger, please implement this on a Pyrex tank. I will buy all of them.