My recent experience with the JBJ has not been entirely good. I got one which I'm sure was defective--it ate up two 5lb c02 tanks in about three weeks. Given that it arrived with a bent meter. Figuring this was the issue, I returned it for a replacement, and this one did a bit better--1 5lb c02 tank in about 20 days. I am now considering whether or not to switch over to milwaukee.
One thing about the JBJ, which may not be specific to it: its needle valve is very finicky. I've spent a lot of time trying to get it to sit in one place, and even when it does, there's no guarantee that it will continue at the same rate the next day.