Bear with as I have quite a bit to relate: I have had three Fall lines (and no not because they don't work!! I still own two of them). I started with the 150mm in my Nomad 3 (XL - rider 6'2" with 34" inseam). 9point8 sent it to me in March 2016 and it set up easily, although the original system of cable end at the post was far more finicky and a PITA to get perfect as one guess-imated and trimmed the correct cable housing length.
As soon as the Digit remote was available I bought one of them and it is far easier to set up.
Wear and tear? I rode 1800 km in training in three months, the 2018 Trans-Provence and guided all summer without an issue.
In November 2016, when it became available, I bought a 175mm dropper as there are times when the seat cannot be low enough with the 150mm!
I switched the 150mm to my fat bike and the only issue I had was a seat collar failure (and not from over torquing) where it cracked and a piece that surrounds the angle adjustment bolt fell away, luckily this happened on the trail to work rather than miles from home on a training ride.
9point8 responded to my email within five hours, I had a return label that evening and the seat post was re-built and returned to me within 10 days which is pretty good in my opinion. As it was not as a result of over torquing they even paid the shipping.
I am fairly certain that it might have been an invisible crack from a fairly big off (fell and flipped 12' off a rock wall into an olive tree, I don't know how I walked away from that one with only scratched and small rotor burn!!) during the Trans-Provence that finally failed and I told 9point8 that the dropper post had had a fairly active life including a few pretty decent crashes. The main point is, that other than the metal failure, the seal was perfect and the action almost as crisp as the first day.
My first 175mm 9point8 developed a leak last summer (full time guiding again so lots of miles and use - I use my dropper more than I change gears on a lot of trails) and it turned out that the schraeder valve core had become loose from trail vibration. I now carry a valve core tool but luckily, at the time, the maintenance chap at Tyax had a valve core tool for his ATV that he let me borrow.
I bought a full re-build kit and after watching the video (and having t available on my phone during the service) I managed a full re-build in about 40 minutes. Other than the brake release tool, which is fairly cheap to buy, it requires no tools that most keen mechanics don't already have in their tool kit.
So the 150mm post did a full (hard) summer and two winters and is now back on the Nomad 3 as it lives with its new owner.
My Sight has a new 175mm Fall line with Digit remote, and 300 km of spring training without a hint of trouble.
My Range has the 'old' 175mm Fall line with Digit remote which has 2800 km (mostly off road) on it but refreshed with a full rebuild kit.
I have also run Lev and Lev Integra (both pretty good) on older bikes and I have used Reverbs on rental/ demo bikes (even with the new remote it is still not as crisp feeling and the seat wobbles). The best I have got out of a Reverb is six days without an issue and I honestly believe that the hydraulic remote is the biggest weakness (now that the post seal overlap issue has been addressed - apparently) and those Reverb owners I know who have converted to something like the DeHy or Wolftooth ReMote Sustain seem to experience less problems.
The question of longer dropper posts exerting more force on the seals is just physics, of course they do which is why BikeYoke are proposing bigger tubes or integrating into the seat tube (34.9mm versus 31.6mm is a 10% increase in diameter let alone the increase in volume and surface area) to make the longer posts stronger and less likely to over-load the seals. But like suspension anything with a seal that experiences some small and continuous amount of lateral load has to be serviced and replaced eventually. The fact is the home rebuild on the Fall line is simple and relatively in-expensive.
Considering how well the Fall line works, how reliable it has been for me, how simple it is to set up and maintain, how there is only an hour down time for a full rebuild, the smooth light action and replaceable mounting bolt of the Digit remote and their customer service I just don't see why I would run anything other than a 9point8 dropper post.
