Last time I seriously tried using it, it seemed unnecessarily CPU-hungry and my battery life suffered as a result. That fact alone was enough to get me to stop using it. I have a weird thing about inefficient software in general, but in this case its inefficiency was actually inconveniencing me. With my good old Vim+tmux workflow, my 12" Macbook claims it'll go for 14-15 hours, though I haven't ever fully tested that claim.