The Saint Pro is the big brother to the Latitude 64 Saint. It is much more "overstable" than the standard version and thus will fight headwinds better. It will likely also cooperate better with your sidearm shots than the original. If you dig the Saint, try the Saint Pro!
Opto plastic is akin to Champion, Elite-Z, etc....it's the most durable in disc golf. This means your disc will hold its flight characteristics for longer than other blends and will take longer to wear in.