I have the RNR 716PS. We haul three fullsize sleds in it. Yamaha Rage, Yamaha Vector and, Polaris 600 Classic. You can squeeze in at least one and maybe two long-trackers, but not three.
I bought my trailer in April 2002. Other than new brakes/wheels bearings and a couple of corroded wires - no problems at all. Very happy with it. Paid $4300 which in highsight was a great deal.
We have put at least 10-15K miles on it for winter trips. I have also used it to move my small JD utility tractor (folding ROPS) which is pushing it on the weight but it handles it fine. It's also been used to help move stuff on more than one occasion from one house to another.
I have also found RNR great to work with. I just contacted them about getting some updates done (new hinges, new flooring, etc) and they are willing to tackle this too. Definitely a company to do business with -