Welcome to our forum.
$13K spa with an EZ Lifter? Makes no sense. EZ Lifter is a functional, but (in most people's opinion) ugly lifter. Dose not give much help on a large, older, heavy, waterlogged cover.
The Nautilus was on my list as well as the Optima. I went with the Optima but I was very impressed with D1's in general and would probably have been very happy with the Nautilus. I liked the feel of the white shell( ultra life) but the dealer could not guaranty it couldn't be stained by my well water. What shell/ colors did you get?