They’re fine sleds for the most part. However, just be aware of their limitations. My experience so far has been that they’ve been fine until it gets pretty cold, as in -20 or so and then the plastic they’re made out of gets a bit brittle and wants to shatter. Have also busted the welds on the hitch/tongues multiple times as well.
As far as plastic sleds go, I’ve never had any issues with my Trailboggan sled (made in Canada, I think) and when it comes to hauling heavy loads over rough country on or off trail the very best has been a Cross Fox sled made by Northern Sled Works. Made almost completely from UHMW and are almost indestructible. Spendy, but will last for many years. And if you are handy, not too hard to make your own custom version that fits your needs exactly.