Count me in as a big ARO fan (the pyrex version, they also sell a poly EVOD look-a-like under the same name). I had two on a pre-order an got some of the first ones shipped - for some reason I was able to stuff a Kanger head into one but not the other (the base just above the threads is slightly larger on the Kangers). Bought two more about a month ago and both work great, but you need to get the Smok heads, which were hard to come by for a while but seem to be getting more common as Smok puts out more devices that use them.
I see no difference in fit/finish or leaking between my older ones and newer ones - all are great and will vape a tank dry without leaks - love my Protanks too, but I can't say the same for them and the AROs are way cheaper. I don't think you'll regret your purchase...my only gripe is the Kanger/Smok head incompatability since I've got dozens of Kanger heads for all my other tanks mostly sitting around.