I have a 2200, the 2100's former .22 caliber cousin. I used to really like that rifle until I got my Crosman 102 and Benji 392. Yes, the 2200 and 2100 are better made than the 760 (die cast receiver), but I've gotten to where I hate that loading port on the 2100/2200.
The 2200 uses a 1377/760 piston with a metal extension that snaps in where the pump cup goes and the cup snaps into the other end of the extension. The 2100 probably uses the same set up. I've had trouble with the two piece piston coming apart while pumping.
Personally I like my old metal receiver Powermaster 66 better than the 2200/2100. Same kind of soda straw barrel, but with a conventional open loading port on top of the receiver.