Great Posts Marc. I'm always grateful to be part of a civil thread with your input. I do agree about the steel. Easier to install. No muss, no fuss, and you do get that cut edge look with less maintenance compared to a cut edge. The only thing I disagree on is dry setting the larger blocks you linked to. This guy lives up north and the frost/heave cycle will make them go goofy in a couple of years. That and if this guy is using a zero turn, he'll move them around pretty easily when he hits them. Ultimately I would still set them in mortar. And as tree rings I would try to miter the bigger blocks to get as small of a seam as possible. http://www.lawnsite.com/attachment.php?attachmentid=191744&d=1276867571 Another thing to consider ATV, is the trees you plan on going around. If these are smaller ornamental with minimally aggressive roots, then I wouldn't worry about the ring placement, as long as it isn't too close. If they are potentially trees that will get large and have large surface roots, such as a silver maple, then I would take that into consideration and try to place the ring to get 20 years out of the edging. And yes, the paddle bit I'm referring to is the rectangular bit they rental house mentioned.