DW and I owned a 1991 Dutchman and in the 15 years we owned it had 3 sets of GY Marathons on it and not a single problem, nothing. Our present Cougar has been thru a set of Duro's and a set of Tow Max Power Kings so far and not a single problem with the tires themselves, but did tear 2 of em up when the fender brackets (cheapo cr*p) came loose and peeled a groove down the center of the the tread (rear tire on each side but on different trips, one Duro & one Tow Max Power King) but they did not blow. We average between 8 & 10,000 miles a year so this spring we've decided to put a set of Maxxis on it. Guess we've been lucky.
PS I rebuilt both fender brackets so no chance of them coming loose again