What, in your opinion, is the best brand of bed edger (you know, for quality, ease-of-use, etc.)? One fella suggested using a trenchblade on my edger unit to do my bed edging. Here is the link (there's a demo video): http://www.trenchblade.com. What do you think? Think it will do a sufficient job for $4.20 a blade? Thanks in advance!!