I'm leveling a 4 man Druid set myself. Currently ~78. My original intention was to level as 3 + DPS and 1 TANK but that never seemed to work out well no mater what I did. After specing Booomkin I've not looked back. 4 Boomkin and I PUG a tank, it makes for a nice smooth run. At level 85 I assume they will be just as viable, and in PVP they are thoroughly entertaining.