I don't plan on getting it, but I actually like the collecting of the shells. That's what we really do on the battlefield for multiple reasons. If I can focus on collecting my brass while there's a chance someone will kill me, I think I can manage it when it's only airsoft. It also provides a good training tool without any missing steps.
I believe it's gas. Looks like there's an inlet valve on the top of the bolt body. I posted it because I thought it might be worth it to someone looking at experimental modification without braking the bank. And if you wanted a show piece, why not get one on sale?