Yeah, I have 2 of those mitre trimmers. I've also had limit success with them. If you're cutting real soft wood, or small cross sections, they're great. Hardwood, big pieces not so much. Funny thing about their construction; the angle in one direction is held by spring tension, nothing more. It takes only moderate pressure to make it go wonky.
Would anyone like to buy one?
Yeah, it's constantly in my mind that the opposite sides have to be that same length. I take great pains to try and make that happen.