The gun springs open if not fired (fully assisted) and opens easily after being fired (partially assisted). Like the H&H style assisted opening mechanism, the guns are a bit harder TO CLOSE than non-assisted opening guns (but this is supposed to be your loader's problem not the man shooting the gun). I don't ever find them particularly hard to close however.
The Southgate ejector system is generally considered to be superior to Avant Tout ejectors. Someone with more expertise than I should expound on this however.
The workmanship is very good on mine. C&H used more machining than the London best gun houses. They were the economy London gun maker. Nonetheless, the hand finishing and engraving is very good. The Sandhurst is a good value but don't confuse them with the Victor sidelocks.
See:
http://www.cogswell.co.uk/ownedtext.htm#33
