I don't want to paint a horrible picture, but I've not had a real good track record with the Marathons. I had a 'bubble' on the inside of our former X10 trailer. I had a belt let loose on our '04 205v trailer. I put the spare on and within 100 miles, the spare blew. It was never used and at proper pressure. So, now I have 2 Marathons less than a year old (which appear to have at least a cosmetic change) that I'm considering bailing on and replacing with some Denmans.
Denman makes a trailer tire with a load carrying capacity of 2830lbs per tire, which is almost 300lbs more per tire than the Marathons. The only 'issue' is that they require 80psi vs 65psi and I need to make sure my wheels can handle the increased pressure requirements. http://www.denmantire.com/catalog/p22.pdf