I've been using a GX CS 4 for a while now with no problems, it's got 24 hrs. of use on it and still works fine. I ordered a CS 2 and got it today; I wanted something smaller that I can throw in my truck when out hunting. I ran it through a few tests, and it really impressed me for its smaller size. The one thing I noticed is that the fill gauge on it is in PSI instead of MPA. Most of the reviews I've seen on it the only negative was the gauge did not read PSI....I don't know if they recently changed them or not.... but, I'm happy with it...