I grew up with B&Os as our family HI-Fi back then consisted of a Beomaster 4000 with ambio and Stereo Quadraphonic system, a Beogram 4002 tangential tracking turntable, both in beautiful teak finish. Whether they are over-rated really depends on the individuals, the system was beautifully made, beautiful to look at and sounded beautifully (as far as I could remember).
The ambio and Stereo Quadraphonic system was the first ever surround system I've ever heard and I thought it was totally amazing; I'm sure it's nothing comparing to the 5.1 or 7.1 surround sound systems nowadays, but back the, it really blew me so I guess I'd always have a soft spot for B&O's products.
I also love the visual design of their products too; however, I think the last great design they made was the Beosound 6000, and they've really gone downhill since. Nowadays, compare to Loewe's products, B&O's look clumsy and ugly.