If you plan on looking at a Zmax, make sure it's the
sigelei Zmax, not the one made by Smoktech. I like small devices in general, so I also like the mini - it has pretty color choices too - but if you are looking for an APV with size options, there is the Sigelei ZMax flat top telescopic. Whatever catches your eye, I strongly suggest you browse the APV sub-forums to see what sorts of problems current owners may be having.
For example, you will likely get suggestions for a Vamo, but if you read the sub-forums you'll find there have been problems with the 510 connector and the gasket (some call an o-ring) around the center pin. I have a Vamo and thanks to reading those threads know to be gentle with it. I just wish I had found the threads about finishes, since I got a black chrome and it wore off in about 3 weeks.