Noxious fumes-emitting lawn mower and weed-eater. Bad.
Electrical lawn mower and weed-eater. Better, but still, we are talking about plastic, electronics, and toxic materials (used in the electronic boards).
Old timey manual push mower and garden shears. Good. The old ones (do they make new ones?) were made of steel and wood, both breakdown in the soil, eventually.
Goats. After they're done mowing the lawn, you can eat them (unless, as someone else has noted, you've given them a name).