Yes, there is, Sunbrella is better, according to the below:
Odyssey III is a lighter weight (polyester) version of Top Gun. Similar characteristics including high strength, dimensional stability, and abrasion, mildew, and UV resistance. Use for lightweight protective covers for boats, dinghies, and grills, or for bags and totes. 6.5 oz. per square yard. 3 year warranty.
Breathe Ability (3): Slightly more breathable than Top Gun, but a little less water
Waterproof (3): An additional clear acrylic
backcoat is applied to further enhance its water
repellent properties. Odyssey III is just slightly more water resistant than standard Sunbrella Marine
Abrasion Resistance (4): The polymeric coating makes Odyssey III extremely resistant to abrasion.
UV Resistance (3): Polyester is a very UV resistant material but less so than 100% acrylic
fabrics like Sunbrella and vinyl coated polyester fabrics like Stamoid.
Colorfastness (2): Surface dyeing color does not stay true as long as solution-dyed fabrics like Sunbrella and SurLast. Colors are also not as vibrant or consistent as Sunbrella and SurLast outdoor fabrics.
Clean Ability (3): Easy to clean, and although a soft tight weave, dirt easily washes free from the crevasses of the yarn. The acrylic coating on one side does make dislodging dirt slightly more difficult than cleaning
non-coated woven fabrics."
Although the UV resistance apparently isn't as good, it does say that Odyssey has better abrasion resistance which is something worth considering in the application you're interested in. Sunbrella is not really very abrasion resistant...
And yes, your sail will perform better with lighter cloth. Speaking of lightness, there is also a UV stickyback product, similar to the stickyback for sail insignia, that you can use for sacrificial strip. It's usually used for small boats and is only good for 5-7 years compared to 10 for Sunbrella.