TLDR: Don't let other people's opinion about tricycle geared airplanes make your decision for you. If the Tri-Maule meets your needs, and is a good, solid plane at a fair price, I'd say "Go for it!"
That Maule looks pretty darn good to me! To paraphrase the old saying "Ugly is as ugly does..." I flew my father-in-law's Piper Colt (underpowered version of the Tri-Pacer) and it was a complete blast to fly. Ever since then, I've had a LOT more respect for that plane (and a lot less respect for my fellow pilots who dismiss them without ever having flown one).
I strongly suspect the Maule would be a total blast to fly as well! As the Carbon Cub NX (nose wheel model) has shown, a properly designed nose wheel plane can take off, climb, cruise, and land with every bit as much performance as its tailwheel brethren... The CC NX, in fact, takes off and lands shorter than the tailwheel version, because it can achieve a higher angle of attack on the ground – even higher than a cub with the biggest tundra tires available.
When I first began looking for a "new" airplane, I quickly narrowed my list down to the RANS S-6 Coyote II. Initially, I wanted a taildragger, and nothing else would do. (After all, I'm a tailwheel pilot, and "real" pilots fly tailwheels.) But I could not find a good example of a tailwheel S-6 with the Sport Wing (highest gross weight, and best all-around performance of the three types of wings they offered). I saw lots of nosewheel versions that looked like decent planes. I finally realized that the tricycle-gear would do everything I really wanted an airplane to do, would cost a bit less to insure, and would have a whole lot nicer manners in cross-winds. And since I could put 8:00x6 tires on the mains, and a barely 1-inch smaller diameter "turf tire" on the front, that should get me in and out of pretty much anywhere that I really had any business landing or taking off... I'm not a bush pilot. There's no "rough field" that I absolutely HAVE to land in. I have to recognize that I'm a relative neophyte backcountry pilot, living in north Texas, and most of my flying will be within 350-400 miles of here.
To me, a tailwheel would be "mandatory" if I planned to land on soft sand, or where there are BIG rocks, or if my only choice for a forced landing would be that same type of terrain – like if I were a bush pilot in Alaska. Or even if I was an experienced backcountry pilot and planned to do serious mountain flying, or to take on some of the more challenging backcountry strips in Idaho, Montana, etc. I'm not going to try to land my airplane anywhere I would risk serious damage if I slightly misjudged... It's more about being unwilling to take the financial risk just to experience the adrenaline rush of pushing the limits. That's just not really me...
So I finally told myself to just get over it, and buy the best airplane I could find, regardless of where the third wheel was located... Shortly thereafter, I found a great, low time nosewheel model, bought it, and am having an absolute blast with it. The STOL performance is amazing to me. The plane stalls somewhere around 32 mph with flaps, and around 36 mph clean. It gets off the ground in well under 250 feet, can climb to 800' AGL before reaching the end of our 7000' runway, and routinely lands in under 250 feet as well.
I'm now working on refining my ability to "hit the mark" on each and every time. I'm close, but still occasionally misjudge the headwind and undershoot a bit – energy bleeds off quickly in a lightweight, high-drag airplane! Landing short of my mark is unacceptable to me, especially if I want to enter any spot landing contests or STOL competitions. Not that I ever expect to win against some of the super-specialized STOL aircraft out there, but I do think it would be a fun challenge...