I love my MkII S10 BB Carbine. The bolt on mine was quite stiff and graunchy, but John Bowkett sorted that out when he did the blue-printing.

Mine groups well with Daystate 4.52mm pellets, although some BSA barrels seem to like Bisley Magnums.

I'm saving up at the moment to get a MkIII stock, which to my eye is much nicer than the one on my MkII.