Best spec to level with now?

[Smag]

I had a good time leveling as Disc. They will love you in dungeons since your dps is very high and you can keep everyone alive with relative ease. Shadow and Holy Priest have far better aoe capabilities though. Drawing hordes of mobs to you with dots will take longer to kill but it's more relaxing as you won't die.

I don't know about relative ease. Healing as Holy is much much easier in 5 man pugs compared to Disc. New leveling scaling doesn't help it either.
I main Hpally, so maybe a somewhat familiar healing rotation comes into play.

[Ladyoftheforest]

I don't know about relative ease. Healing as Holy is much much easier in 5 man pugs compared to Disc. New leveling scaling doesn't help it either.
I main Hpally, so maybe a somewhat familiar healing rotation comes into play.

Mained a Disc for a good period so was already familiar with the spec. Sure, there were headless-chicken-groups and caused a few tight situations, but normally it was easy. The extra Disc-dps (sometimes I was top) provided probably helped a lot and I was also using the perk Light's Judgment. Didn't level as Holy so I'll take your word that it's a breeze in dungeons. Did you use heirlooms?

[Spicymemer]

shadow is the fastest, go for the dispersion heal trait first.

[Smag]

Did you use heirlooms?

Yes I did.
Basically, you'd have to pull half of a dungeon to wipe (which we did at one point in Strat) in Holy.