I was having a play earlier today with the talent calcs, and was wondering if anyone knows the duration (not cooldown which is 15 sec), of Archangel and Evanglism, as the durations aren't listed in the mmo DB, and I can't access wowhead at work.
I can't give you an exact answer atm with the beta servers down, but it's long enough for it to be up constantly. The number 18 seems to be about right.