I have the sci fi booklet and I LOVE the format and general idea - More games should embrace the zine format.
The actual rules I couldn't really get on with - I found them a bit clunky and unintuitive, which is a shame as I was quite excited for them. But that's just me,YMMV.
I will however recommend Patrol Angis from alternative armies, As I find that to be a very fun system that fills much the same niche as USEME.