SMN wrecks BLM in T2, assuming you don't have really low dps group that takes forever to kill anything... if so you might run low on mp at the end, but I think the situation for this is small considering how easy the content is.
I like BLM better on T3 just because there is a bug currently in pudding phase, if the pudding is dead and u were casting on it before it died your spell will go off regardless if its dead or not and will refresh AF/UI/Eno making it very easy to max damage all the time.
In T4 I think its more suited to SMN due to quarantine taking so long to put you there/spit you out you lose a lot of seconds on your UI/AF which often makes enochian refreshing a nightmare, especially if you get the first quarantine or taken multiple times. SMN is more consistant dps than blm here.
That said, I still blm in A4 over smn because fun. The only one I really whip out smn for is T2. BLM is way more fun than smn in anycase imo.
I fucked up so bad I'm afraid to say the order I chose . I think the consensus is to rush legs though, and neck/ring priority, after that it doesn't seem like it really matters much at all.
Aikaal dropping the masterrace bomb!