I've used them (several sets) and will not use them again nor would I recommend them to anyone that pulls their trailer on the road.
Goodyear finally told me they could no longer honor the Marathons replacement warranty but did set me up in their Wrangler LT tires on all of my GN/pintle trailers. Tire usage and down time on the side of the road dropped by 90 percent.
IMO the Marathons "may" make good fish shelters or a tire on a trailer that doesn't see much road time at interstate speeds such a lawn service trailer that its life is spent running around town or a utility trailer that sits 90 percent of the time and trips less than 50 miles/etc.
I would upgrade to a LT tire if possible especially if your on the road a lot. However which size and load range depends on your trailers axle ratings and what size your current OEM tires and wheels are.