With the right amp and room (preferably big) the Apogee Centaur Minor can sound amazingly good. For real bassheads there's not enough low end, but it certainly can keep up with modern day speakers. Just make sure the ribbons are ok: nice and straight, nothing curled, with good tension - they should move a little when you blow (very gently!!!) at them.
New ribbons are being made in Australia, and although the price is reasonable, the cost of new ribbons and shipping makes this less then a bargain. If necessary of course: my own Centaur Majors still have the original ribbons, which are in perfect condition. So it might be a good buy, just make sure your amp and room are up to it.