I think it is much harder to go wrong w/MP than CP as long as you use a good base. I like SFIC, which I buy from Wisteria Lane in 50 lb logs (cheaper that way), although BB sells it as well.
I would respectfully disagree a little bit about shelf life of MP soaps, but it might be b/c I use the extra hard clear base from WL, which contains less glycerin, I think. I find that *my* MP soap is better if used in 6 mos or so, otherwise it gets harder, less pretty and generally not as nice b/c of the glycerin loss, even when wrapped.
It is good when CP loses water/ages because you want the hardness and the curing, to a greater extent. W/MP, since there the saponification has already occured when you make it, I think bars are best almost as soon as they are made and then after a much quicker period of time lose the bloom, some.