In terms of both waterproofness and durability, the order (by best performance) is Polyester 190T, Ripstop Nylon 15-20D, Silnylon. Also, the poly does not stretch as much as nylon when wet.
Your ranking system leads to a tie. For $130 saves you less than a pound, gives you more room, but have to contend with the inconvenience of silnylon. The weight saving is not that much unless the rest of your pack system is optimized. The room should not be an issue unless you want to have the option to sleep 3-people. The silnylon issues are not a big deal but they will be more noticeable as cuben fiber takes over the ultralight market. I've made the upgrade and will never go back to the skating rink, sagging, and misting of silnylon.
Based on your previous posts, you still need to upgrade other gear to reduce your base pack weight. I'd recommend taking a hit on tent weight now (< 1b), investing the $130 into a lighter pack or sleeping bag (the Big 3) to get the most bang for your buck. When everything is optimized, then upgrade to cuben fiber when (hopefully) the cost will come down.
That will be $0.02, keep the change.
