I have been following this thread with much interest as I have owned or flown most of the aircraft mentioned except the Piper, Aerostars and MU2 Turboprops. This includes all of the Cessnas SE and ME with and without STOL, tip tanks or wet wings off grass and paved with only a few exceptions.
An important reservation is the on field service support for the older out of production aircraft. If you buy Commander or MU2 then make sure that there is full service support at your home base, if an Aerostar make sure service at both ends.
The Commander range have fine cabins, good handling but the cost of the engines in the 685 is now $$$$$$+ to overhaul?.
Is you intend to fly overwater in a single piston with family and friends then make sure it is low wing preferably with 2 doors.
Check the useful load on the fully equipped aircraft as later models like pilots gain weight.
The Skymasters should be considered as being suitable for 4 adults + maybe a couple of kids or the dog. The seat base on 5 & 6 is only about 5 inches off the floor and very uncomfortable.
Keep the debate going as there are some good words of wisdom from established posters but lots of crxp from bloggers who obviously have never owned, flown or importantly had to pay for the maintenance on the aircraft upon which they pontificate.
For me a well maintained deiced STOL T337H with upgraded autopilot, avionics and an understanding engineer,wife,bank manager.