Lots of people do! - This is the second lot of Quad gear to fall into out hands recently and my colleague said his phone was ringing all night when he put it on Gumtree!
And that "Slope" function (furthest right) on the amp is interesting - it works like a variable loudness button and works very well indeed.
Hifi purists would probably never even think of turning it on though?
And if you think DINs are bad, you never want the sheer, unalloyed joy of wiring-up a Bulgin plug. Health and safety cannot have been a high propriety for its designer!
The Disc and Tape Adaptor boards are interesting too - Little four-sided circuit boards that you remove, turn and replug to impedance-match different hardware. No ICs either - beautifully made handwired/soldered items.