I have a green gas nbb UHC H&K USP .45 (non-clear, but identical clear version is available). It's pretty much the same grade of gun as these things. It's a piece of crap. The 350 rating is with .12g BBs, which translates to about 270 fps with .2g. The only thing the fixed hopup is really any good with is .12g BBs. You can get decent range with those. .2g BBs and above get shitty ranges. It's not very accurate past 30 feet regardless of what BBs used. You'd be lucky to consistently be able to tag a man-side target at 50 feet.
I would personally avoid these things if you're intending to game it. If you want it as a plinker and it's no more than $75-ish and you have money to burn, then go for it. Just don't expect it to last long or be a useful gun.