After much going back and forth I settled a couple years ago on the Pulsar Trail XP50.
Initially I had issues with it holding zero...wasn't bad really, few inches here and there but enough to cause concern for long range shots. I hunt areas that give 300-500 yards and more opportunities. My longest night kill so far is just under 400 yards. I captured it on video and have posted it on here a couple times.
Sent it in and within a couple weeks had it back with updated firmware... so far, so good. I've started a log to track the changes but have taken the summer off from hunting. Between getting the unit back and the start of the summer, I think I made one adjustment of about 1 1/2" and that was it. So long as I'm killing things and hitting relatively close to POA, I haven't checked it.
Hands down a game changing piece of gear for night hunting... glad I made the jump and glad I spent the money.
Friends can't believe I dropped that kind of money ($5K) on a thermal but when I compare my night hunting hobby, which is mostly what I do, against other hobbies like fishing (boat, motor, trailer), it becomes clear the money spent is justified.
The customer service from Pulsar has been second to none.