Manaburn

I would really like to discuss Manaburn and if it is viable or not. As I have not chosen it as an AA ability yet, but for some reason the SK in my group last night determined that I was not as good of a wizard as I could have been because, well, I did not have Manaburn. As for reference this comment came up after Torkler, so I will use his fight for my "numbers".

See in this group I was in last night, even if I did have MB, I would not have been able to use it. Group makeup: SK, warden, mystic, illusionist, monk, and myself. For most of the night I was fighting every inch of my life for power. I was down power and more power, hit canni, hit manastone, hit essences, and so forth. I was putting out a steady bit of DPS, and then hitting Catalyst/Ice Nova at 40% and continuing after with my other spells. No aggro, except once.

Torkler was the most mana intensive one. Now I can't tell you that I was using this mana due to group makeup (which I really do think it was) as I have never had mana issues like this before, but, well....

Okay, I don't have a parser and I should really invest in one, but here are my approx numbers for the Torkler fight. I really tried to explain this to the SK, but alas, it didn't work. So bear with me a minute here, as I rack my good ole brain.

Three glacial winds = 12000
One surging tempest = 8000 (I cant remember how many ticks this spell is, so for my sake going with 8 @ 1000)
Three Iridates = 3000
(Ack I cant remember the spell name, its the icicle debuff) 3x = 1500
Four Ball of lavas = 16000
5 sunstrikes (yes I use this very quick casting spell =p) = 5000
Incapacitate 2x = 4000
Protoflame (he never died, so pulling a number off the top of my head for this) = 2500
Ice Nova = 12500
grizzles/char/dementia (ill buff/proc) = 5000 (and I think that was the low end, as at one time all three hit at once for almost 2k)
And I sure I missed something more in there. Maybe a 5th BoL or maybe I did hit IN twice (I think I tried but was resisted).

So what does that equal? About 70000. And I really seem to think that is on the low end.

Now I have approx 7500mana. So manaburn would equal about 37500.

That's half of the damage I did on my own without it. Now, in this fight with Torkler, my mana went down with his health. Torkler @ 75% health = Krys @ 75% mana, and so forth. So if I were to wait to cast MB till half health I would hit for 18750 plus half of above (35k) = 53750 damage. Too much decrease and now I am a duck in the water with no mana to continue on with, save busting butt to health drain myself back up. If I hit MB at the beginning of the fight, you would have 37k in damage and one dead wizard.

So in my belief MB is really not as great as it sounds. Will I get it in the end, probably, but there are other abilities that are much better for me to spend my points on at the moment, to give me better steady DPS, then straight out burst DPS.

So, tell me. Right/wrong/indifferent? Show me more things, maybe I really am thinking all wrong on this ability, but maybe not. I am very interested in the different schools of thought on this one.