Great question. I know Mooneys well, but RVs not so much, so my analysis of the comparison is based on perception. I believe the fuel burn will be lower, so there is an on going savings. I think the repair parts will be cheaper. I know the price for upgrades to the panel, or any other part of the plane will be cheaper. I think maybe the annual inspection will be a little easier. I suspect the insurance will be about the same, but I haven't explored that yet.
Two other factors that are motivating me on this trade is one, the Vans will be newer and having worked on Mooney now for several years, I am tired of old. The other is if I want to change something, add something, upgrade something, it's no big deal. With the Mooney, it's a PITA. Technically, changing out the sun visors for better ones is illegal as there is no STC for my plane. The same goes for changing the interior lighting to LED fixtures. That's the stupidity I'm talking about.
Replacement parts for the Mooney are not hard to usually, but they are expensive and sometimes they aren't available. When Mooney goes into one of it's reoccurring near bankruptcy phases, all the parts that fail all the time dry up and most do not have STC replacements from anybody else.
Case in point- The rubber coupling that connects the Ram Air valve to the fuel servo. It's only available from the factory. It is 1950's technology and is pretty much a $300 POS. It has a limited life span. If the factory doesn't have it, you are in trouble. Patching it with RTV is verboten. Finding a good used one is very, very difficult as they are all in some state of decay. It's not something an owner can fabricate. Flying without it is not an option. There have been those that have set out to make a replacement out of new, modern materials and sell them, but once they hit the FAA wall with the STC process, they all give up. 60 years of M20s and the factory is still the only source.
The Vans does not have this kind of dumbassery.