Aery vs Comet

I think they basically do the same damage over the course of a game. Aery has really no cooldown, when it comes back you can use it again. Comet has 20-8 sec cooldown. I'm not sure if CDR effects these. Aery you proc 100% of the time. Comet is esy to dodge. Aery procs even on basic attacks, any attack. Comet only procs on abilities. For sure Aery if you are sup, even if you just have heal and no healing or shield abilities. Has anyone done extension testing on these to compare? Actually Grasp of the Undying also has nice damage over the course of a game. I have been using that for top. :)