I've got a dozen of them and love them. I use a pneumatic upholstery stapler and shoot a pile of staples across the backside of the trim with one staple leg on each side of the mitre. I got the idea for the staples on-line somewhere, maybe Gary Katz? Between the pressure supplied by the clamps, the glue and the staples it makes for a strong joint. I find then process to be faster and better than the usual approach to casing. Well worth the cost if you install casing regularly.
J