From my perspective I thought Caroline's 576 was terrific, the glory days of Johnny Lewis and Jay Jackson was our morning radio in Colchester. Laser 558 was great but listening all day it did get a little repetitive. The good thing around that time is if you didn't like a song a quick switch of two channels and you had a great alternative.
I also loved Caroline 558 up until the mast came down, was sounding great and had a terrific audience in East Anglia where I lived at the time.
It wouldn't work today as radio is a different animal and there's so much choice.
There's a lot to be said for there being too much wood to see the trees as there's so much choice, but that makes it so much more difficult to find the new Kenny Everett, Steve wright, Tony Allen or Bob Lawrence.