For the touring bike the Marathon Plus I found to be just too heavy, I tried those and hated them, but they wear long and are an extremely tough tire; so I now roll on the Conti Contact Extra Light 700x37 folding with reflective sidewalls, this tire so far as been extremely reliable, last much longer then Vittoria Randoneurs, and fairly fast rolling but again this is on a touring bike so who cares about speed. The weight of this tire at 476 grms scared me because they are on the lighter side for a tough touring tire but so far I haven't had much in the way of flats but I do run a flat protection strip in the tires as too eliminate flats even further. The Contact Extra Light is not knobby but it's design does allow some degree of traction in rough stuff and it has reflective sidewalls. The Marathons are better in loose situations like gravel, but what little gravel I run into hasn't been a problem for these, basically it's just a good all around tire that performs well on asphalt and off road but not stellar off road.

I tried many touring tires but overall performance edge goes to the Cont I mentioned above.