Wasn’t aware they were available over here. Or do you mean PT80?
The 90 appears to be the old Beretta lookalike non-blowback pellet-firing PT80 re-skinned to look like an HK USP.
Reviews of the PT80 are probably a good place to start. I have one. Can’t say I’ve used it much. Got it used in excellent condition cased for £30-35, but that was a fairly good deal. £50 would be about all I would suggest giving for one (and, honestly, I’d rather put that £50 towards something a bit better), though I’m sure guys on Freeads etc ask more. An OK cheap plinker, not a patch on the (much more expensive) Umarex guns. Quite light and plasticky. On a rough par with Crosman 1008. Crosman CB40 is better.
Hope this helps.