Fairly positive that the NoMar is adjustable for different tire diameters. Not sure about the TireXI met the guy that made that TireX changer referenced on Sept 8th at a local cars and coffee a while back. He says he's at local tracks changing tires and obviously promoting his product. It looks really slick and especially nice to be able to wall mount. His price is $485. Seems like that's about the price of the lowest option No Mar but its been a while since I looked it up.
I'm not sure it's as versatile as the no mar? It's hard to justify buying a tire changer when I can take a wheel in and have it done for $30. Other than convenience. Is the no mar helpful to change other small tires (atv, lawn mover, etc..)? This Tire X doesn't look like it would be that versatile
however, at 30$ a charge thats a lot cheaper than it is out here! Quoted average was 80$ for a rear tire swap with the wheel off the bike last year.