I'm feral spec, and love it. However, I would like to try all three trees for druid. I'll try Resto when I'm closer to 70. But when would be the best few levels to try out Balance? Around 45 or so? I'd like to try it before level 50. :)
People always do it as soon as they hit 40, but to be honest 43 or after is the better because then you have access to dreamstate. Dreamstate will make the transition from a melee-er to a caster much easier due to enhanced mana regen.
The best time is around 50 though. Treants is a good bail out for when your new to casting and accidentally pull to much. Very powerful ally when you are in need =)
I tried boomkin at 43 and while it was quite a change from feral to a mage, and I could kill quick, about same as feral, still the "downtime" which is unheard of in feral, killed it for me and something felt wrong, so I respeced back to Feral and haven't looked back yet. As for gear, I bought best I could in AH since I have 70 for gold, so there wasn't a bias. I gave it a fair shot, 3 levels of boomkin.