They would fare better if they played some more old material but, and I'm a huge Mastodon fan, they really are a band that are much more fitted to a club-sized venue. I just can't imagine their music translating well in a big amphitheater in the middle of the day or whatever.
6/17 - Meshuggah
6/28 - Iron Maiden - Bergen, Norway
6/29 - Blaze Bayley - Bergen, Norway
7/1 - Iron Maiden - Luxembourg
10/31 - Fleetwood Mac