I just purchased the 4-in-1 12". It came highly recommended by a friend of mine who has been using his for about 8 years. I have not received mine yet, so I can only pass on the recomendation of my friend... Good luck!
I purchased an older foley-belsaw sometime ago. I have found it great for moldings but a little slow on planing. Changeover takes a good bit of time. You might want to take a look at RBI. If I remember correctly, they have a system where you can change a shaft and not the individual cutters. I have a friend who has a Woodmaster unit that he purchased new but doesn't use it because of the excessive time required to change it. A few years ago, I had a wood master sander and found it to be a real nightmare.