I asked the same thing last year and was told I wouldn't really need it so I ordered one on an end of season sale. It seems pretty stout on my magnum but to be honest I've only been out a few times this year and Ive used neither the Otter Sled or hitch. I used my old smaller/lighter jet sled on my smitty. In comparison the Otter seems much stouter and heavier and I'd be surprised if it broke under normal use. Are you using one that failed?
If you need a fix ...My old Jet Sled hitch failed the first day I used it many years ago but I'm tough on gear. I ran cable through the conduit arms and snapped beaners into loops formed and secured with two cable clamps at the sled end of each arm. It hasn't failed me in 15 years since I did the rebuild. Having said that the Otter seems bulletproof too but unless I'm hauling out multiple folks on my Foreman the JS holds everything I need and it's lighter by a bunch.