Fire V.S. Frost - leveling through RBG's

[:1]So yea, I am mostly planning on leveling through random battlegrounds and curious of what peoples opinions are about leveling with frost or fire spec. The way I see it, but I may be way off the mark as in the past my highest level Mage was 8 o_O. But, I see fire as being able to nuke, which seems good for sub-85 battlegrounds and frost as the more tactical control your enemy and whittle away at him which is good for arena/duels. Does it matter if you have heirlooms or do not have heirlooms?(I will have full heirlooms but my brother leveling a Mage with me will have none)

Any other opinions? Did not find much on the topic on these forums, or any forums for that matter.

Background info - me and my brother just started playing again via scroll of resurrection. We started on a completely new server based on one that would roughly meet both our needs. I will be transferring over a character with heirlooms, but my brother will have none.
Frost and fire make for some sick combos with shatters. Personally I would go frost (especially with heirlooms)
Fire. All day every day.

Frost's survivability basically turns a 1 shot into a 2 shot. It isn't enough for the burst you give up.

I ran BGs at every X4 and X9 interval from 49 on. I had probably 6-7 different games where I was 19:0 or 19:1. I had several instances where I engaged and killed 4 people simultaneously, including Rogues/Ferals/Hunters.
I have an 81 mage now as frost and I demolish pretty much anything I look at.

survivability is amazing, I would totally go frost.
frost is best because of ice barrier /thread
Once you can get ice barrier, frost becomes 1000% better than fire imo. At my level, my glyphed ice barrier absorbs more hp than I have. Effectively having 8-9k hp at level 58, as well as not having my casts delayed is huge.
Xiun well even as 85 u demolish anything u look at..
Even though I prefer fire at 85 by far low levels frost really is the way to go.