Chain mortisers are a love hate situation for me. They can rough out a big mortise in knotty oak pretty fast, but there is always just a bit of cleanup in the bottom/ front face that takes a lot of time. When you figure in the huge cost of the machine (SwissPro), plus maintenance and replacement parts, I don't think they are really as much of an advantage as a lot of people think. Being efficient with hand tools and selecting good timbers and laying out round defects is part of being a good timber framer, in my opinion. Buying a lot of expensive tools so you can just blast a bunch of rough holes in low grade timbers is an indication that one has stopped their journey towards being a highly skilled craftsmen. I know that will upset some people, so everyone just needs to remember it's just my opinion. I know that at the end of the day my arms will be a lot more tired running a boring machine over a CM, but my back won't hurt as much as if I had been running the mortiser.