it is interesting that this thread compares the 'best' of Quad pre/power with the 'least' of Naim.
i had a 'loan' of a Quad 33/303 setup for a period in the late-60's early-70's, long before i discovered Naim. the pre-amp was good but the power amp was very flabby.
neither could hold a candle to comparable Leak pre/power combos of the same era.
i seem to recall that the Quad FM tuner was better than the Leak, but i'm not absolutely sure. i had a Leak Sterofetic tuner, and it was very good indeed.
sadly, Leak was taken over by Rank, and that was the end of that.
i spent quite a few years in america and canada, and had Yamaha, Luxman, Crown, Lexicon, AR, Stax and other equipment - some of which was very good.
i subsequently revisited Quad 405's etc, but by that stage Cyrus was coming on the scene, and i don't think any bit of kit produced by Quad cin the 1080's and after can survive side-by-side comparison wiith Cyrus kit.
i discovered Naim late, in the later-80's. a second hand hi-fi shop in notting hill gate was getting rid of three Nap-135's for £100 each! and a repair shop in oxford had a Nac-12s, a pre-amp power supply, and a Hi-cap.
as i had a real interest and a enough spare cash at that stage i also bought second-hand AMC, Lexicon, Sony and other equipment - whatever was going through the dealers at good prices. i had AR, B&W, and KEF speakers, until i discovered Ruark - the finest sounding british-made speakers of 1980-2000, period.
anyway, coming back to Naim, i bought a 42.5 (mellow, but not exact), 60 (OK), 32.5 (excellent), 72 (superb - with a Hi-cap nothing ever made by Quad comes close), 82 and then 52. i still have my Nac-12s (modified by Naim to run from a Hi-cap), which, powered through a Supercap, is in the same bracket as a Nac-52. this is not to say a Nac-12 is as good as a Nac-52 - just that it will knock the pants off just about anything else.
so, thumbs down for Quad (except for the electrostatic speakers, which treated well are superb). thumbs up for Naim.
the 'worst' Naim pre-amps IMHO are the Nac-42, 42.5 and 60 - but they still compare favourably with the 'best' that Quad has ever made.