20-40 does seem like the slowest bracket... once you get 35-40 and hit DWM it speeds up a bit, Tanaris at 40 and a full ZF quest clear is just crazy XP.

Hit 50 last night on team 2 with 2days+3hrs (Priest/Mage/Warlock x3)
Team 1 hit 60 with 2days+12hrs (Boomkin+Shami x4)

The caster team has really started to get good with decent AoE heals, dots and hellfire+AE+HN when I feel like chain pulling around 10 mobs... Finishing a couple of Tanaris and Hinterlands quests up tonight and then on to WPL/EPL for the final stretch... should be 60 by the end of the week, then it's on to team 3 (hunter x2 + priest x3) and prepping my boosted Paladin for WotLK 60-80 (With a DK)

RAF rocks!