It looks to me as if you could use any regular-throat machine in this frame. It comes with handles to "drive" with:
http://www.superquilter.com/testimonials.html
It does seem that there are two versions of the Super Quilter frame: one of them a tabletop version. The older ones came with square poles, which seems very outdated. You might want to check to find out if the Craigslist one is a standalone frame or a tabletop version, what kind of poles come with it, and whether it comes with handles. (You need handles to move the machine around.)
The current website says the suggested retail price is $900, but it looks like it could be less with their "sale" pricing that seems to be on all the time. Might be worth a call to find out what their "sale" price is:
http://www.superquilter.com/
It's hard to find a machine quilting frame for $225. If you want to set it up for use with a domestic machine, then I think this is a fair price -- although I would offer less for it. Assuming everything is there, it should work fine with your Brother as long as you are okay with the limited space. One reason for offering less is that this frame is not well known, so you may have difficulty selling it later if you want to upgrade.
A comparison frame would be the original Hinterberg, which sells new for $650:
http://www.hinterberg.com/prod-Origi...g_Frame-5.aspx
Probably the biggest question with a frame like this is how good the bearings are, which affects how smoothly you are able to move the machine. If the frame is set up so you can "test drive" it, you could tell from that. It's possible to change the bearings on a carriage, but it's extra cost and extra work (and requires some DIY expertise). If the frame is in pieces, you might want to offer less for it since you cannot be sure all the pieces are there.
Hope these ramblings help some.....