It's funny to read someone slag a band, and then put up the peace signs. Just say it like it is, and accept that people will hate you for it. Have more respect for your own opinions!
I don't like John Mayer that much - I find that while he is very talented, he still isn't stretching it enough. I would more consider Peter Gabriel (during the So and Us period, especially, the time of "Sledgehammer") as a good example of art and commercialism, as well as Sting circa Nothing like the Sun and Ten Summoner's Tales (the latter of which I think is a good example of commercial and artistic success, overall).
Of course, John Mayer can play circles around them on the guitar, and probably looks better. There's that for him. But his songwriting and general level of overall talent? He could do better.
I would like to note, however, that I find his cover of "Bold as Love" to be impressive, as well as "Who did you think I was" (I hope i got the title right).