I've had tonneau covers, regular caps and now the Leer TSC 600 Hard Tonneau cover.
I live in Rochester, NY, and decided after a couple of winters to do away with the idea of a soft cover. Snow load is one, but the bigger issue was security. You can never feel safe carrying anything valuable under a soft cover.
I have had the Leer TSC600 for three years now on my duallie and love it. I'm 200 lbs and can stand on the top and it doesn't even flex. It's color matched exactly by Leer to your paint scheme, and I never worry about security.
Drawbacks? ( ... there's always some

)
It hinges from the front, so if you want to get something at the front, you're on your knees.
The other is more obvious. I can't haul anything taller than the cover is tall.
Were I to do it over, I would get one of those systems I saw that fold up in sections when you want to haul something tall. Because of the TransferFlow 50 gallon tank against the bed front, I can't use anything that "rolls up", as it requires 9 - 12 inches of dead space. Might want to remember this if you have any plans on getting an auxilliary tank installed.
With the exception of hauling something tall, I love my Leer.
