I use an Alroh Imp edger. I used a Bosclip long ago, but I found I'd rather use a handwheel than that thing: no power to speak of, and wheels barely over 1" diameter, so it would get stuck on a piece of gravel I could barely see. It also used up a blade in 2 trips around an 8 metre by 15 metre patch of grass. The Alroh is probably also harder to use than a handwheel, but I keep telling myself that when I become proficient with it, it will get easier (I've only used it twice.) I do think that if I were doing long straight runs on grass that hadn't spread so much that you can't find the edge of the path, the Alroh would be a dream. In practice I find that big patches of out-of-control kikuyu, badly-poured concrete edges, and weirdly curved mowerstrips (well it seemed like a good idea at the time) make it slow work that produces pretty ordinary results.
