Stew meat I brown first before cooking. I always cook stew meat on top of the stove since its a tougher cut. However I know what you mean. If you cook it too long it can become too mushy and have a boiled effect.
I also have cooked corn beef in it and it turned out wonderful. I have to be honest and tell you I am still learning. I do have a book by Lorna Sass that has lots of great recipes. I made pinto beans a couple of weeks ago and they were great.