I had to fill my 9L tank today as I was down to 3000psi and I figured that instead of doing it at home, I would use my old Yong Heng that I keep at work. I had repaired/replaced the entire cylinder head a couple of years ago and that thing has been aces ever since. I switched to using a 5 gallon bucket of distilled water with water wetter in it a year ago and that works surprisingly better than cold tap water some how. My temp now, doesn't keep spiking up anymore, it just levels off to a temp that is lower than my old shut down cut-off temp was. The unit stills fills fast too. I can bring my 9L tank @3000psi, up to 4200psi in 13 minutes. Not too shabby to me. I usually am just filling a 2.17L tank from 2800 to 4300, and that takes less than 5 minutes. I keep thinking that I will replace them with something quieter but they just keep going. It would seem that once you work through whatever problem they show up with, they just keep running. I still have a brand new one, in an unopened box, that I got a couple of years ago to replace the next one that died, lol. I think that they're 8 years old at this point, they take up a lot of room, are loud, and kind of a pain, but if they keep getting the job done, they stay. I don't see a tenth of the posts that I use to see about YH's and I figured that was because people moved on or up, but maybe it's because theirs aren't breaking down either.