I actually returned mine because it wouldn't do the entire lawn on two batteries. I've gotten a corded one to replace it, rather than buying more batteries.
The problem was never the power, but the endurance. What's been your experience with that aspect?
I can mow my entire lawn with a single battery charge. I'm using the 5Ah battery it comes with, which is the highest capacity cell they make for these things. Supposedly they last long enough to cut 1/4 acre of lawn, though I dunno about that figure in particular.
Oh, glad to hear it. Mine's just too big then. I gave it a chance when there was much less growth but it just couldn't do more than about half of the job on the 5ah battery it came with and the 2.5ah battery my trimmer came with.