I have a HFC glock 17, bought second hand... previous owner had not used it for 3 years, with no gas in the mag, and it still works, no leaks no nothing... the Glock 17 is not a clone, it was made before the tokyo marui one... i havnt had a chance to use it in a skirmish yet... but its quite accurate... (just as good as my freinds TM P226) the only problem i have with it is the fact that it does not take TM products (including the mag, so there a b*tch to get hold of) they do have a decent gas consumption though (around 1 and a half mags)
Personally I like em... but I would go with Tokyo Marui or KWA over them any day