Ok, so I had a traumatic evening with this question tonight .. I was balance, then changed to resto, but the limitations on the spell possibilities and casting times were really, well, hard to manage. And I am a long-term (2,5 year?) Druid, mostly resto actually. I think that resto / tree form could be really helpful in 10, 20 or 40 man raids - where yu never get nailed, but in small 5-man instances, when you sustain dmg sometimes it's not feasible.
So, i re-specc'ed back to balance, with a few more points in healing/resto. i took out the extra nonsense balance talents, and put every extra point into better healing so i am - well - 8-% balance / 20% resto, and before that i was an ok healer too, so i think i can be a good guild healer now too, better even.
Dan / Mizh