He didn't like the internal air flow controller......you have to unscrew it from the mod to get to the AFC, and his was very loose, sometimes when taking it on and off the mod, it would change the airflow.
He cut himself on the bottom edge, cuz it was really sharp.
He doesn't like having to undo a screw to fill it. He mentioned with the kfun that you could top fill, capture the air hole yada yada, but you couldn't do that with this one cuz you also have to hold the tank on, it doesn't screw on.
one of the screws (well all of em, just don't recall which one he was referring to) is very deep inside the wall of the bottom part, so you nearly need to have a magnetic screwdriver. and of course, the screwdriver that comes with it really doesn't work, but most of em don't far as I know.
Overall strong thumbs up though. Just some things he really didn't like, but mostly he did.