I just recently bought the Supermax 25-50 off a member here for $1000 and it's a great machine, and I think I got a great deal on it. Probably too big for my shop, but I made it fit
It is
heavy. 369 lbs according to the shipping weight.
Reputation-wise, Performax and Supermax are probably the best for open drum sanders, and I would give Supermax the edge. Performax was bought by Jet, and the Performax designers started Supermax. The machines are very similar, with the Supermax having a few more features (like a wixey digital depth gauge, optional upgrade). If I were buying new, I would still go with a Supermax.
The grizzly drum sanders are a real PITA to change the paper. Maybe they've changed in more recent models, but you'd have to tape the ends of the paper to the drum, instead of a clip.
If you're looking at the used market, I would avoid any Deltas or Ryobi's. From what I hear, the parts are hard if not impossible to come by if they break. If your budget is under $2k, then you can afford much better.