Hybrid polymers, like Stixall and CT1, tend to have a higher silicone content, which makes the sealant more pliable and more difficult to penetrate. I always like to recommend this type of product because they are high quality, and they also serve as an adhesive (in case you have more than one type of job to do outside). If you just want to seal a roof or a gutter, then I would advise getting the Soudal Roof and Gutter Sealant (to the right), because it is cheaper. The good thing about hybrid polymers is that you are less likely to waste silicone in the tube, as you can use them for several applications, both internally and externally.