I have my eye on the PM. For me, that is a good size for every day use.
Go to the store, try both, fill them with your stuff--see what works best!! Then, ENJOY!!
Boku, do you have the measurements for the MM? If not, here they are: approximately 17.7x11.2x7.9 inches. This should help you get an idea of what size you think will suit your everyday needs. Hope that helps.