I had a Miracle keyboard and they're great fun - I'd say well worth £50.
When I broke my Amiga setup in 2002, I got £70 for it. make sure it's complete though - the foot pedal often gets lost and it's pretty useless without it. Oh, and it interfaces perfectly with Bars and Pipes perfectly :-) No need for a midi interface either as it can connect to the paralel port (although the k/b does have midi in/out).
