Well, the spec here is a benchtop lathe to replace a 7" x 12" Gingery in a tiny 6'x8' shop, and fit on an existing benchtop, so really big or heavy machines, while better for sure, don't fit the requirements. Within the range of 7 to 9 inch lathes, and 12 to 20 between centers, a 9x20 like the Grizzly at over 250 lbs is probably even pushing it.
The existing Gingery lathe is probably about 60 lbs with a 28" overall length. I suppose I could come down to even another 7 x 12, but then it would really have to be better than what I have now -- stiffness to part off surely, or do reasonable size profile cuts without chatter, and quick change gearbox (or NC thread cutting) would be the attractions, otherwise, I'm fond of the little lathe I built, and certainly can deal with the "spares" issue -- I have patterns for everything and a furnace!
John R. as an owner of that specific 9x20 model, sounds good and I trust your judgement.
I do know that what Pekka says is also true in general, since I own, and have tuned up/modded where necessary Asian machines (bandsaw, round column mill drill, 50" slip roll, tractor mounted wood chipper, listeroid diesel genset) so I'd be going in with my eyes open. I wouldn't expect everything to be the way I wanted it. But I would expect lots of cast iron for a benchtop lathe, straight hardened ways, a good size hollow spindle with taper and low runout, and a working quick change gear system.. Those are what I miss most in the Gingery at present.
I have read up about what the complaints are for the 9x20 specifically: needs additional bolts to fasten carriage (published mod), lacks tumbler reverse, slowest speed is 150 rpm, no back gear, quick change gearbox only accomodates 8 speeds without manual gear changes. Mods exist to solve most of these, and I actually have a treadmill motor and controller (a common mod), which can solve the speed and reversing issues.
On the other hand, I keep thinking about what I'd do in building my own lathe. I think about it a lot. Doing things exactly the way I'd want them. You'd know it fit the space, You'd set the specs you liked. And it would probably cost less than a new one and yet have good size and quality purchased chucks, etc. I think about, what if I do end up modding an Asian lathe -- how much time will that save over starting from scratch, and will the result be equvalent? There's also the pride in something you made yourself. That, even now, makes it hard to think about replacing the Gingery lathe.