Below is what I've owned to date.
-Trijicon MKII 35MM-
Owned for 1 year now (currently still have).Sometimes while NUC'ing the screen will go to snow. Refreshing it again will take care of it, more annoying than anything. I'm told Trijicon will fix it, but I just don't feel like sending it in yet. Best thermal I have owned, built like a tank, turrets are awesome when hunting in the Iowa winters, and the picture is awesome.
-Pulsar XQ38-
Owned for about 6 months now (currenlty still have for my buddy gun). Few issues I've experienced to date would be the battery cap has popped off a few times from the rifle recoil, and there are some flickering lines that will appear on the screen.
-Armasight Zeus 336-
Owned for about a year, buddy owns it now. Probably wouldn't purchase this scope again due to the price compared to others available, like the Pulsars. Did have to send it in once due to the blue screen of death. Customer service was pretty good, didn't have any issues on that front. Biggest complaint with that scope would be that it was a battery eating fool. I had to build a coat for it in the winter and shove hand warmers in it, otherwise it would eat a fresh set of batteries in 15 minutes or less. Would never recommend the 60hz model for anybody looking.
-ATN Thor HD 640-
Owned for a year or so. Didn't care for the display screen that much, it had this wide screen type view that was hard on my eyes. Also, this was the scope that made me realize I don't need all of the options it had. The menu was ridiculous with "features", took forever to get to where you needed, and forget doing it quickly in the winter with gloves on. BUT............. I know people love to hate on ATN, this was the only scope out of all the ones listed above that never had any sort of technical issue with it. While I didn't care for some of the feature and functionality, the picture was good and it always worked.
My goal for the future will be to turn the MKII into my buddy scope and get a REAP as my main, or see how the N-Vision stands the test of time. Will also probably add a thermal drone at some point in time. And some sort of night vision for walking around and driving the buggy with.