You can install our site as a web app on your iOS device by utilizing the Add to Home Screen feature in Safari. Please see this thread for more details on this.
Note: This feature may not be available in some browsers.
Don't know what brand you may be looking at and if it'll make a difference from the reviewI looked at, but this makes it appear that it's an improvement on cosmetics only.
I bought/installed both, but did it just for looks (to give it that finished look). In my opinion, they do not help with reducing noise or provide any benefit in terms of heat insulation.
I did both, a couple years ago, and like GreenHokie, they're mostly for aesthetics, a finished look. I doubt there's an insulating benefit, and the noise? If there's any benefit, it's tiny.