I had a Roll N Lock on my last truck and have a Retrax retractable tonneau on my new truck. The Retrax is far superior, the hard surface is much easier to keep clean, it opens and closes much easier with no straps, and locks in any position with the keyhole being easily accessible on the drivers side of the truck. I also think it looks much better.
I have no problem locking it in front of my fifth wheel hitch and do it every time I tow. I also like the fact that it will retract fully into the canister and still gives a full view of the bed including the fifth wheel hitch while hitching.
I don't know for sure how it would be in frozen conditions but suspect it would be fine. I would not hesitate to recommend one.
