Good job, a little bit of creativity thrown in there different from the original. The guitar is a tad off rythmically at a couple points...nothing big. You hit a couple dead chords. I like the voice, i think you did a good job in your Mayerish voice (new word???). The only problem i had is it seemed you dropped a half note below key a couple instances. Either that or your chord was a half-step off lol. Either way, still good.
ive never heard the original also but wow dude you really do sound like john mayer... most of the time people here say to stop copying this or that but that john mayer voice you do sounds really good.
guitar part is good too.
