I honestly didn't know of the 771 having any alignment issues, but maybe there were problems and that's why it's on closeout already. I didn't think that saw had been on the market for very long...a year maybe? The alignment issues with the 715 are well documented, as are the alignment issues with the Ridgid 4512. Still yet, if at all possible, I'd get any of these three saws over a rusted piece of unknown from Craigslist. Odds are you wouldn't get a lemon, and if you do, Grizzly or Home Depot will take care of it (returning a saw would be a big inconvenience though)
Depends on how you use the items I guess...do you have the bosch saw for
"field work"? Otherwise I'd ditch that first. What do you use the shopsmith for? If I had one, I'm guessing I would only use it for a couple things, which wouldn't justify the large footprint. But that's just me.
Also I"m in a small 1 car garage that still has a washer/dryer, water heater, and a slop sink in it...and I've managed to fit quite a few big tools in there with careful organization. So...you should probably move in first and try a few different layouts before you sell any of your tools.
Where I think it is most applicable to is in adding gentle curves to your work. Whether that is machining the actual part, creating a template, or creating a bending form for a bent lamination. Also it would be ideal for scooping out a chair seat. But here's a couple more cnc heavy designs of mine.