I've got a Mk2 S200 in .22, with a ten-shot conversion - I use it as a dedicated NV ratting rig - it's light, and small, and manoeuvrable (great when tip-toeing around a farm-yard). The light-weight is important, as by the time the NV scope, torch, IR illuminator and gubbins are attached, it adds up.
Shot count is quite low, but the plus side of this is it isn't too hard to fill with a stirrup.
Mine, with scope and pump was £320 after a bit of haggling (though I was at least the 3rd owner of this gun, and it had a few lumps and bumps). This was last Summer (2011). I've done nothing to