My experience with the Bauer Junior II has been great. I believe it to be the best of the non professional hobby compressors(Bauer, Coltri, MaxAir, L&W and so on). It usually costs more than the others but I didn't ever regret paying a bit extra for that kind of quality.
I bought mine new, back in 2000. I'ts first job was to transfer 60000 Liters of Helium to 300bar storage tanks, with a couple of short breaks the compressor ran 11hrs that day.
Since then it has run 1200+hrs filling tanks with air, transfering helium from one storagetank to another, and keeping 2 argon storage tanks topped off to 300Bar over the last 19 years.
Change the synthetic oil every other year, never pump argon when the compressor is hot, or for longer than 20 minutes and it'll just keep on running.
At one time I also had a Capitano and a Mariner, but finally sold them when I stopped selling gas to other divers. Over the last few years all the tech divers switched to rebreathers and suddenly I wasn't making any money putting 150L of Helium in a diluent tank or 2.
The Junior II stayed and it still treats me well.
Micheal