I have an SB 8K, but I haven't put a lot of hours on it yet. Much sturdier than the LMS 8.5x16 which I consider its direct competitor, though I don't think its worth what Grizzly is asking. I bought mine with the intention of CNCing it, so the lack of QCGB is moot while being a real PITA in the mean time. Oh and the ****ty 4" chuck they ship with the 8K only has a .8" throat so you can't make use of the big bore without a new chuck, on the flip side of that the 5" 3jaw D1-3 they sell is really nice! D1-3 native chucks aren't very common either.

I have no first hand experience with the G0752 or G4000 so I can't give you a comparison of the castings, but I was satisfied with my 8k compared to the Sieg(LMS) 8.5X16. If your going to keep it manual I don't recommend the 8K, its a solid little machine but being able to cut threads easily is a big deal.

EDIT: Check the general metal working sub-forum, http://www.cnczone.com/forums/genera...ew-sb1001.html