Kind of same thing with Tiamat. MB will definitely help a lot; 30% additional damage on whatever base damage we get is more than any amount of Magic Attack Bonus, Etude, or INT+ equipment can get us, and all we need to get this huge bonus is correct timing. (To put this into perspective, magic bursting vs. not is about the same dmg difference as a RNG shooting, eating yellow curry, then shooting again)
However, on the flipside, its hard to time this, especially in alliances. Many times I notice there is a SC set up for MB'ing, but its not properly communicated (at least, not CLEARLY) WHO is going, and WHEN, to make WHICH skillchain. Many times during Gods I will start casting to time a MB because I see a WS go; many people still have SC call macros even if they are not in the SC, and that makes it very hard to burst. After some more refining I'm sure we can get this down and drastically enhance our performance and thus reduce battle time. During Tiamat, Aqua and I were either on Stun duty (no spells cast, watch chat log) or on stand-by, which meant either resting or casting a spell or two (often times Stoneskin reapply, Curing, maybe drain or aspir)
A well timed SC with MB every contact, on Ouryu OR any other mob, will drastically help ^_^ We do OK with this, but I think its something we can realistically set our goals on improving.
Edit: I speak mainly of BLM here because, alas, I am of the BLM mindset. However, consider: Last tiamat, we had 5x SMN. If every Spinning Dive was MB'd, that's 30% more damage. In one round, that's 150% extra Spinning Dive damage; that's instantly like adding an additional Summoner, and more. To all the people who say "we only have 3SMN online atm" consider- MB'ing instead of not is instantly like having 4