Re: My reaction to Mastodon...
I saw the same bill you saw at the beginning of their current tour. I was a little trepidatious about it because I've heard, and seen, enough video evidence to warrant the 'they suck live' rep that gets thrown around.
Musically they were 100% spot on as you say and Brann Dailor was flawless. I thought there was no way he'd execute all those insane rolls and fills he's known for . . . dude nailed 'em all.
There were some odd vocal moments but they were minor at best. For example, during the chorus of 'Spectre Light' they had a special mic and it was either not on or down so low in the mix to be non-existant. Even Brent Hinds sounded fine who is historically the vocal weak link.
One thing that bummed me out though is they did not play 'Oblivion' at all. Love the intro and the drum buildup so boooooooo.