I chose to level my 4 druids as boomkin, bought cloth shoulders and chest, staff, trinkets. I have a 5th druid(i know it doesn't apply to your situation atm) which is already 80 and geared as both feral and boomkin. If your intent is to quest, by all means go the feral route on all 5. You will kill stuff so quickly, and in lower levels running too and fro will be much quicker. Downtime will be less as well. This has always been the plus side of druid leveling, slow to no downtime at all as feral.

My thoughts on leveling as boomkin: Well i didn't really want to grind out a full set of boa gear for feral because i'd already ground down the caster gear for my shaman team(and i intend on leveling priests as well so thats why i got cloth)

I use my druid already 80 to tank instances but i've found that 4 boomkins in pvp once you get starfall and typhoon to be pretty much /faceroll to win. Its faster than instances, though you can still do daily instances if you had tree feral and 3 dps(any would work i would think caster or feral). Any way you roll it it will do well, though highly gear dependant once you get higher level. All in all druids are a ton of fun