As always, late to the party, but for what it's worth I've been flying Maules for eighteen years and as we have maintained quite a few of them at Aerotech, I suppose I have ended up with an opinion of course!
Maule can be a bit of a Marmite aircraft if you read the various flying forums with lots of knockers and lovers! However, most do agree that they are a rugged, capable aircraft that are comparatively cost effective to buy and maintain. There are also some people that proclaim that they are a handful to fly and difficult to land in crosswinds, especially the tailwheel version and here I believe is the key word,... tailwheel. Personally having built up the experience of flying our M5-235C from a 400m strip atop a hill with lots of curl over and turbulence from surrounding trees, I rely on the Maule for its sturdiness and solid feel on approach in gusty conditions. Crabbing towards touchdown in strong crosswinds and with a late, but precise kick off the drift, its own momentum will invariably hold straight long enough for three point touch down without any lateral drift.
Unfortunately, I can only assume that experience has not been coupled with the tailwheel factor in many of the landing accidents that have occurred over the years and given the Maule its unwarranted reputation, when really the blame should be on pilots pushing their own personal boundaries too far, too fast. This is no doubt due to the allure of strip flying and the capability offered, provided the necessary competence has been built up through training and practice.
So having emphasised to a prospective owner the importance of steady safe progress as Maule experience is developed over time, the crosswind factor will simply be added to the other new skill sets as needed, such as short field landing and take off etc. Then the Maule comes into its own in terms of all round capability. For having taken off from a strip with 4 passengers and bags, the excellent fuel capacity easily allows you to complete long legs as if you have swapped its Cub like strip-ability for an Archer like touring reach. I have been to Lithuania and back in a couple of days, including a night IFR leg from Bydgoszcz in Poland to Hamburg for the ILS between the Lufthansa airbuses. And on the subject of long distance touring, I would add that due to its stability in the cruise, I would never consider adding an auto-pilot to its panel, simply a waste of weight in servos and money.
Some of the cons include the build quality, which is nothing compared to a Skywagon for instance, but then again this is partly offset by the comparative cheapness in Maule parts.
Another factor if you are looking at the US to buy, is keeping it on the N-reg, as if you want to go mad,.... like some do and add the huge Tundra tyres, then realistically it needs to stay on the US register for the STCs.
That said VGs and gap seal kits make a nice addition and can be fitted to G-Reg Maules. These really allow silly speeds to be flown, but the aircraft is fine without them unless you want to enjoy that extra enhancement and controllability at a relatively small cost and negligent weight.
Finally just a note that the many variants M4, M5, M6, M7, M8, M9 also have many sub-configurations. The wingspan can be two feet shorter on the "same model" or the fuselage can be longer (M7 or MX7) as well as different lengths of aileron and flap! This has big effects! And needs to be considered as part of mission evaluation before purchase!
Overall as you can see, I'm a big fan! We have organised Maule fly-ins to our strip in the past and will try for another later this year once flying life returns to semi-normal!
All the best!