I have two Presa 75TCs in daily use (and a couple more in the stash, since I like 'em so much!), both coming up on 2 years. Zero problems.
Fire button below/beneath the screen isn't really any different than one that's not, it's just that you don't directly touch the button. So longevity should be about the same.
The 75s are getting hard to find, the 100 is, afaik, still easy to find. It's designed for 26650, but comes with a sleeve adapter to use 18650s. A bit bigger to contain the larger battery, and I've not handled one of those to see about hand feel

The 75 I find really comfy in my hands, and the whole "squeeze" design is great for those times when the vaper is seasonally gloved. No trying to poke a little button through padded finger tips!
And the 75 is a perfect fit for any 22mm tank.