Well put. I have a little over 450 hours in the "Yellow Peril" now and have few regrets. For the money the M-4 is under valued IMHO. That being said there are some weak points. The first fundamental truth with aircraft is that everyone is a compromise. Some will do most everything well and fall on other points. Some do a few things exceedingly well and that's about it. Line up your priorities and see what weaskness' you're capable of living with.
Maules (M-4) This is the "short wing" of the bunch. I have the IO-360. It is a very expensive engine to OH but it is very smooth, good on fuel and is a delight to fly. W/regards to floats, this one area is a fault. There are few prop options and that combined with a short wing, I think a J-3 might beat you off the water. That being said, for the last 5-6 months, I have been operating off of a 6-700' rough strip at weight with trees to clear. OK, granted it was no more than 60 degrees and at 600' MSL but My last load Monday was two adults at almost 400lbs (tl), 3 Labs (60-85lbs each) a 22 lb survival kit and 42 gal gas. This plane (Maule's in general) have one of the widest operating envelopes for the buck.
Insurance is a bugger though. I got lucky and got mine before it got too bad and have mananged to still have what I consider to be cost effective even up here.
My take on the Franklin: I have had the pleasure to meet the guy in OK who is most likely the US expert on the Franklin. He claims that is still viable to find a plethora of parts around the US and he stated a number of reasons as to be optimistic for the future once P&W gets their act squared away. (I have faith in the guy, he did the pre-buy on mine) It is a very strong engine albeit in my opinion it is a little rough. It is carbureted and has little heavier fuel burn as my 210. I believe that there are a couple of options on the prop too. There are a number of planes running around with Franklins in them and I've never met anyone who has said that it would make a better boat anchor. I have a couple of friends with 'em in their M-4's and wouldn't trade.
The other sleeper is the old Stinson 108 series and the four-place T-craft. Really cool planes, a number of STC's and quite a following. I'm seeing a number of 'em up here that are seemingly forgotten and have entertained the idea of a project or two. (No, the YP stays with me) My AI is selling his 195 and is looking for something a little more utilitarian. Everytime he went up in the YP, he'd come back with a grin.
Keep in mind that the Maule's up until recently anyway, will have the fit and finish of a farm truck but If I were running with the Bonanza crowd, NOT.
I'll spend a little money for a glass of good Scotch and a nice Cigar though....
