I've got a Bosch 36V mower. It works fine and has enough oomph to cut the (smallish) front and rear lawns unless it's really long and / or wet. I plan to buy a "bare" (ie without battery) hedge trimmer in the Spring to use the same battery.
My advice would be to get the biggest (width) you can stomach cost wise. True for any lawnmower in my books but these aren't cheap. However, there's no smelly fuel or exhaust fumes, very little noise, no cables and it's lightweight.
Murray