I researched a bit and landed on the Orion which can also be the smallest. I'm not a fan of bottom buttons & prefer them on the side but that's my personal preference ergonomically. From what I've read it has the perfect cap in how its both sized & shaped allowing some of the best flavor & vapor. That's an element which was apparently nailed beyond many other hybrids. The cons are that it may require some modding in the form of sanding down the
tank to fit perfectly without o-rings but thats going to change with the new version due to come out shortly after new years with
tanks that wont require any more sanding. It will also have adjustable air holes from 1mm to 1.6mm in diameter allowing the user to adjust this based on their preference and will have a new unique method of delivering air to the wick which no other hybrid on the market has right now, but enough about the new unreleased Orion V3, lol.
Anyway, the Orion is the only hybrid I have so I cannot comment from personal experience using other devices, but I've done some research. One complaint I've heard about the Zenesis is that they tend to have an airy draw and the top cap pops on & off with o-rings which some like as you can easily adjust air-hole placement and others dislike this saying it can pop off in your pocket.
Every device has its own pros & cons and each model has hoards of devout followers willing to suggest theirs is the best. It boils down to doing your own research of opinions owners have about the pros & cons and take into account what you personally like the best.
I recently got interested in Petar K's Vaper which is unique because of how slim it is and even more so, because its the only automatically activated hybrid where instead of using a button on the bottom or the side it is activated by your lips pressing on the mouthpiece. I'm on the list for the new version of the Vaper but haven't ever used one. Again users have given it good
reviews and have also pointed out some things they wish were different, similarly with the new version of the Orion, Petar K took these suggestions into account when he created the new device which should eliminate the complaints associated with the first version.
Just my thoughts and mabe a lil exra. Good luck with whatever you choose! I'll be interested to see which you pick.