To P or not to P, that is the question

[Flyer22]

I am looking into the various costs of owning and operating a 337. I am currently in a toss up between a P337 and unpressurized, T337.

The pros of pressurization are obvious, while the advantages of unpressurized aircraft, other than costs, seem to be in the higher certified service ceiling, ability to seat 6, and possibly more interior space. Can anyone verify?

Can anyone quantify the additional costs of operating a pressurized Skymaster such as maintenance, training, and insurance?

Thanks