Wow, I had no idea they was selling for £300. I picked mine up about 2 years ago for £200 brand new haha.
Personally out of the choices above, I'd go for the Aug. Lovely to use and ergonomic too.
As cool as the F2000 is, a buddy of mine had one and it was very specific with what mags it would take, no idea if that was just his though but it definitely put me off.
But of course, just my two cents!