I got tired of mixing the gas and oil and got a Black & Decker cordless battery. It does my whole yard twice on one charge and I have about 1/4 acre and some woods in the back that I try to keep trimmed. My only problem with it is, they say the line is self feed, but that's BS. One thing I do like about it is, when my line goes down, I pop off the top, pull the line out a bit, and pop it back on. Easy to hand feed and easy to change a new line. I love having the battery power. No more yanking for 10 minutes on a machine that won't start.
I have the 24V NiCad battery. I need to buy a second one so I can charge one, while using the other. I've had this for 2 years.