Compared to pyro and rage, both of which have some intervals between burst combo phases, MM has no such downtime, it is on a constant burst. Even our worst attack, snipe delivers 3200 on crit. It is trailing behind those two in the first global cooldowns but after that it rapidly catches up overwhelming them by a huge amount.
Same goes for canage, it is faster than MM when gore is up. But then MM catches up. This is what makes MM special, we never run out of "juice" when putting pressure on somebody, which means that MM is mrore capable to outlast when somebody used their defensive CDs to mitigate initial damage burst.
Flameburst crits far more than snipe when you include the dot it applies.