I have muck boots and like them a lot. The material is truly a wonder in terms of comfort range; I wore them today to the ski slope and for shoveling the drive, and throughout the winter for running in and out; and I wear them all summer for walking the dog in the yard, gardening etc. They are not really warm enough to be warm on a really cold day, and a bit too hot to work in on hot day, but are great for everything in between.
I have thought about taking them for early season canoeing. They are waterproof and warm and comfortable to wear, fairly light, and would float if you had to swim. They would be reasonably supportive for portaging, not nearly as supportive as a hiking boot, but at least as good as sandal. I had LLBean boots for about 20 years, and really liked those too, but the muck boots are better in just about everyway, but since the bean boots could be tied, they might have been slightly better for portaging.
I am not sure about how quickly they would dry in the field though, if you got them wet. They don't really absorb water even when immersed, but they hold the dampness for a long time, easily overnight if you didn't do something special to dry them. So they would be good for trips in which you were not wading in creeks or rivers that could go over the top.