I feel that just about all of the B&O 'tables that are generally available in North America, and produced after about the mid-1970s, are equal or better in performance than an entry-level Rega such as the P3 or Planar 3, and yes, I have directly compared them. That is, provided that the B&O is in good working condition . . .
Having said that, some are better than others. I'm personally using a Beogram 4004 with an MMC20CL right now, and it's outstanding - better than sooo many "accredited" audiophile turntables. But this machine dates from the late 1970s, and I've seen lots and lots of BG4004s and 4002s . . . and they usually need some skilled work to bring them back to their original performance.
The BG8000/8002 are also very good, and generally a little more consistent than the 4002/4004s, but again, restoration/repair is NOT a job for a beginner. The Beogram TX is based on the BG8000, just with a simple belt drive instead of the eddy-current magnetic rim drive.
If you're not wanting to have it worked-over and brought back up to spec, I'd recommend a later-model linear-tracking turntable, i.e. the BG5005, BG5500, or TX2 to use your own phono preamp, or a BG4500, BG6500, or BG7000 with a (very good) internal phono preamp. Most of the time these 'tables are either obviously broken, or they work perfectly.
If you're interested in a 4000/8000 series 'table, then I'd recommend Soundsmith as a great resource for repair (and of course cartridges for all B&O 'tables). But I'd definately stay away from the early-1970s models with synchronous mains-voltage motors, i.e. Beogram 3000, BG1200, and BG1900.
In any case, a good B&O turntable/cartridge will give you the best tracking performance in the business, and some of the most effective suspension isolation . . . all with virtually zero setup and the convienence of automatic operation.
