While looking through Archive.org earlier today, I found that John Mayer has quite a few concerts up online, which I didn't expect, given how prominent of a musician he is. There's not a whole lot of recent ones, but there is a bunch of ones that date back to 2002 and a little earlier, and from those, I found a couple of cool covers.
All of these covers are pretty faithful to the original, except Crossroads, which seems to lend itself more towards Eric Clapton's fantastic cover of it. Never Tear Us Apart is a decent cover with a Mayer flair , Free Fallin' is a nice rendition, very easy going to the point where I think I like it more than the original. Crossroads pulls out some of Mayer's fantastic guitarwork, although this version seems to have been recorded before he really started trending that way in his major records.
Never Tear Us Apart - INXS
Never Tear Us Apart (INXS) - John Mayer
Free Fallin' - Tom Petty & The Heartbreakers
Free Fallin' (Tom Petty & The Heartbreakers) - John Mayer
Crossroads, Live 1968
..Crossroads (Robert Johnson) - John Mayer
I'm On Fire - Bruce Springsteen
..I'm On Fire/No Such Thing - John Mayer