I dont doubt that you have had good luck but it all comes down to expectations. If this compressor is there just to inflate the occasional flat or low tire .. it looks to fill that role. However, if you are looking for a air compressor that will re-inflate all your tires after a day of off roading I would look elsewhere (personal opinion). Even with the VIAIR after filling 4 tires I need to let it cool down before letting anyone else use it that forgot or has a faulty unit.
The specs you want to look at is Duty cycle and 0 - 34 PSI R18 fill time. You will see other compressor manufactures try to dummy this number by putting 0-24 PSI R14 or something like that to show its filling fast.
I know that a few people on the trail have had other compressors ( I dont know if its this one, $50 is a great price ) that crapped out on them on the second tire --- or the thing just fried itself. The most common one is that after 1 hour its still trying to fill the last tire and everyone is hanging around wanting to leave but does not want to leave anyone behind ...
Again dont know anything about this compressor -- but usually you get what you pay for -- sometimes there is a diamond in the rough and I hope you found it ...