I've got one of those lathes out in my garag, er, shop! I've had it since the late 1990's. So far, the only problem I have is that the headstock and tailstock do not quite line up, which is frustrating for pen turning (but doesn't affect bowl turning much--more on that later). The best mod that I've done to it was to put a sheet of 3/4" ply in the base and loaded it up with bags of playground sand. I think the lathe is maybe 4-500 pounds, and there is very little wobble.
I've seen the HF lathe, and while they may look similar, there are some differences. The Jet has some spindle indexing pins, not so on the HF lathe. On my Jet, the handle on the back of the tailstock isn't cheap plastic. It's still plastic, but it has a heft to not and doesn't feel like a whiffle bat. The toolrest extension on the Jet is beefier than on the HF lathe (but it might be different now since my lathe isn't a recent one anymore). The HF one seems like it has more speed settings, but I don't remember it's lowest setting. The Jet's lowest speed is 550rpm, which is kind of fast for a big out of round blank.
$500 seems a bit high for a used model of this lathe. Is the one you're looking at white or the old-school greenish-bluish (mine is the this color)? Accessories that come with the lathe should include tool rest, tool rest extension, banjo, tailstock, spur drive, live center, face plate, knockout bar, and two spindle pins (one threaded, one not). There's probably something else, but nothing else is coming to me.
If you get a chance to examine the lathe, take along a drive center (or something with a #2 MT and a point) and an 60degree live center. Put one in the headstock and one in the tailstock, then see how close the points are to each other. On my lathe, the closest I can get them is between 1/16" and 1/32".
Hope this helps! If you would like me to check something specific out on my lathe, feel free to ask.
