I know that Sacarathe deleted this question, but I decided to answer it anyway, because it offers the potential for good advice on a topic that is relevant to many of us...
1st off, I haven't heard of any particular criticisms of the CYMA P90, so I expect that it is no worse than most manufacturers' efforts and, despite the price, probably better than some. However, it is a P90 and, yeah, I must admit to a violent bias here, I mean I fucking hate 'em, but that aside, I'm not sure many people, except Stargate SG1 fans, who go airsofting for the first time, would think of a P90 as cool looking. That leaves the only advantage as a loaner being its size and weight - it would be easy to drop in a bag as an extra gun and few mags to take along with your own gun, mags, and gear. But there are plenty of small assault rifles and SMG's with folding stocks, to mention but a few: AKS-74U/N, G36C, HK UMP, 4" barrel M4...
With the exception of the UMP, the mags of those all fit into pretty standard, cheap, pouches (such as 90's era British Army gear) and/or cargo pants pockets, whereas a P90 mag is an awkward bastard even if you have the right pouches - probably easier for total noobs to deal with a standard underneath mag change too, regardless of where on their body they carry spares. G36 mags can be a bit of a ball-ache, with those side lugs getting caught on the cloth of pockets or pouches, but of course they can also be double stacked quite easily, so it's swings and roundabouts in terms of pro's vs cons.
In short then, I would say yes, indeed, anyone would regret buying a P90, of any description, as a loaner...