I have Marathon Plus 38cm mounted on my hybrid (Univega Via Carisma that has 700c wheels.) I got 38cm because i found a guy selling them on a closeout sale (he had a failed business.) They seem indestructible and I have never had a flat though on my road bike with cheap CST 25cm tires i get flats all the time and i hate those tires.

On other bikes i have one with Specialized Armadillo 25cm and one with Panasonic Panaracer Pasela 1.25" with Kevlar (that bike has 27" wheels and options are limited for 27" wheels.) I have had absolutely no problems with these tires. THe only ones i have that I hate are the cheap CST tires.

From my limited personal experience i am on the fence whether i want to get more Marathon Plus tires because they seem resistant and heavier than the Specialized Armadillo and Panasonic Pasella tires with Kevlar. I feel any good tire with Kevlar is probably sufficient for my local commuting / biking needs, i dont really need the extreme nature of the Marathon Plus. But I will never buy tires without Kevlar/flat protection again,. The only reason i got these cheap CST $20 tires on one bike is at the time i was only going to use that bike on a vacation for 2 weeks, but then i decided to keep it.