I think it's a total crap shoot with the square bottles. I picked up two multi packs, and the 5m size all seem fine in mine, but the larger ones crease and whiten at the corners when squeezed, indicating they will fatigue and crack there. I have only tested a couple of them though. I am running a 5ml square in a 14500 mini to test it out, so far so good...I need to try some of the Vapeage 9ml bottles out for my Grands.I got the mixed pack, I think there was 3-4 of ea. size...the first one I used as Rudy stated was really thin and the cap wasn't the best so I just tossed it into the box 'o' dead vape gear...until I built this new mod and I needed a super short 18mm wide bottle...so I figured I'd try it again, I must have grabbed a different one as this one is actually pretty thick...it's probably just a fluke cause all the rest are meh...
I agree, the Vapage 9's are my bottle of choice as well.