I have a Yong Heng compressor also. It is a great little workhorse for the money! I would prefer a Fahrenheit thermometer as well, but never felt it was really an issue important enough to change. I just make sure it doesn't go above 60 degrees and use it. I don't have a tank yet, so I am just directly filling my Air Venturi Avenger, AirForce Condor, and FX Wildcat MK3. It rarely takes longer than 1 and a quarter to 2 and a half minutes to fill any one of the three guns and doesn't get anywhere near the 60-degree temperature where it needs to be given a cooling-off period.

I have a YH going on 3 years now, and I've had my share of 'issues' with. Like many things new there are bugs to work out.
I would say the second stage rings were the most annoying. It made the compressor run longer which ultimately made it run hotter which lead to other problems.
Once I swapped out the top assembly it's been very reliable filling my Acecare 6.8L SCBA tank which I fill to 4k + -.
I top it off when it reaches 3k and don't run it past 15-20 minutes run-time. The temp rarely goes beyond 50 degrees C.
Running it in a basement that never goes above 75 degrees F and 60% humidity helps a lot.
I understand the newer units are pretty trouble free once you take care of it and don't work it beyond the specs.