We bought an Adco custom fit RV cover for our 1707T through Camping World. I chose the one made of "Sunbrella" fabric. It fits extremely well and is warranted for 5 years.
It has been on our trailer out in the hot Tucson sun now for over 2 years and still looks and "feels" new. The material is very strong and has shown no tendency to tear. The tan color helps it blend in a bit with the desert landscaping in our "backyard".
I highly recommend this one, but suggest staying away from ones made of a different material.