Being a bit bored I have just done a 'content vs ads' count of HFN & RR from January 1984 (85 pence).
Ads = 72.5 pages (Including back cover, inside back cover and inside front cover.)
Content = 68.5 pages (Including front cover, contents page, letters and crossword.)
So - almost - 50/50.
But the articles and the features and letters and reviews (of equipment LPs and CDs) are so well written and absorbing that they are easily forgiven for the - slight - preponderance of adverts. In fact, many of the ads are a damned good read too! (Thanks Harman Kardon especiallly.)
The product photographs (in the 'content') are much smaller and less frequent and the fonts smaller. A recent WHF? can be read in a lunchbreak. A 1980s issue of HFN&RR could probably last a couple of days and still demand some re-reading (especially with legends like Barry Fox writing for them).
This Audiolab review was over four and a half pages long (including the lab report) so you can imagine how much there was to read in the whole magazine. You also have to actually read a review to find out if they liked the item (at the very least the conclusion which, just by itself, could run to more paragraphs than an entire WHF? review). Nowadays you get a big photo a star rating and 'For' 'Against' columns and a couple of large print paragraphs (concerned mostly with how much 'wallop' it has) written - and part pasted - by some marketing intern probably.