I have one of these, I really like it and it tends to be used often as my daily box. The sound quality is good, it goes loud and has the DSL button which fills in the bass, this has to be switched off at higher volumes though.
I think it appeals to me so much as it has a great tape deck with nice soft touch operation, good sound and volume, a proper line in and lasts for ages on batteries. It's no M70 in the sound department though, for what it is, a mid size box, it sounds good though. It has no seperate bass and treble controls, just a tone and the lovely DSL button. I have had 2, paid £20-£30 for them so $50 sounds about right I guess.