I love the features of the Sun Mountain, but the pneumatic tires and their hassle with flats has kept me from buying one. If they put a semi-hollow, no air-up tire on them, I would probably buy one. Meanwhile, I am using a BagBoy 440LT with the optional third wheel. It does a pretty good job. But I think pneumatic tires on a push/pull cart are not worth the possibility of having a flat tire.