That’s a great question and very hard to answer. In terms of studio work I’d go for the spell that produced Selling, The Lamb and Trick. Here you have a band so full of composers and arrangers at the peak of their powers in a particular style that they were straining to stay together and so one had to go. But the collective efforts produced sublime music in that prog style that never lost its humour, drama, sense of melody and purpose. For live work, Daryl and Chester brought with them an edge that complimented the improvements in technology and available resources to produce a stunning live show. So that early 80s period is probably the peak for live stuff. I was thinking recently that in the 1979-81 period when I discovered the Genesis family of music they managed to turn out Duke, A Curious Feeling, Smallcreep’s Day, PG3, Face Value and Spectral Mornings, Ant also produced Sides, Back to the Pavillion and 1984. That’s a lot of very good music to produce in the period between the studio and live peaks I’ve highlighted. What a band!
So true! What an incredible run of music!