The Moody Blues
In 69-70, I was still under a certain amount of somewhat liberal parental guidance: liberal, in that I was free to trek to a local Blind Faith concert, but not so free that I could stake out an event like Woodstock or the Isle of Wight - that would take another 2 or 3 years, by which time I was freely hitchiking up and down the East Coast at risk of life (more than once)
In retrospect I do wish I had been a year or two older - so that I mgiht have gone to Woodstock. Most of my stars were in line - except my age. Similarly, I think I have always had a back-of-the-mind hankering to "do" the Isle of Wight Festival/Concert. This need probably stems from the 1970 festival rather than the more recently revived but similarly ostentatious iteration.
For about 2 years, the Isle of Wight festival (back in 68 or so) was a work in progress. The Isle isnt highly conducive to the likes of "flea-haired" hippies : the indigenous are mostly folks with yachts and large yards, rather sedate and preferential to their 5 o'clock tea types. So much so that they ended up putting a kibitz to the whole thing after the over-board '70 program.
But it's the 1970 program that earned its reputation., Granted, since the chow came back on line in the early 2000s, there have been many many bug time acts: the Stones etc, etc. But again, it was and is the 1970 program that remains the name of legends.
It is probably instructive to look at Jimi Hendrix's too short frestival sojourm: Monterey Pop, 69 Woodstock and then 70 Isle of Wight as indicagtive of the times and of his trajectory
Not the best of venues or circumstances (the operators lost big-time money/ the sound system and stage setup were apparently pathetic), I would have to assume that it was a combination of the alignemtn of the stars (hippie speak for just plain good karma) and a pretty damn good selection of artists.
Four days that included: (from Wiki): Cactus, Chicago, The Doors, Lighthouse, The Moody Blues, The Who, Miles Davis, Joan Baez, Joni Mitchell, Jethro Tull, Sly and the Family Stone, Ten Years After, Emerson, Lake & Palmer and Free