I got a couple ego-w kits in yesterday, Iv been abusing mine on purpose. Seems the manufacturer of my model used a decently thick plastic, so I don't see any issues with cracking as of yet. Iv put about 7ml through it already. The coil stays nice and wet and I am not noticing any carbon buildup yet either. Iv actually managed to all but destroy most of my 510 atty's and even an Iken Cannon 2.0 in a matter of days with buildup on the coils. Must just be the way I vape, but so far so good on the ego-w I will post more news after a few more days with the same one.