After playing LoL a lot of time, reaching level 20 and then playing Dota 2 for a couple of days now, I can safely say Dota has the most broken mechanics and heroes of them both.
First of all, these "nukes" heroes have are way over powered, taking 80% of your life with just their Q. Second, stuns have unholy duration. A 5 second stun from a non-skill shot ability? Pfffft. A 1.5 stun is already game breaking, more than 2 seconds is making it overpowered.
I prefer champions getting nerfed every now and then and having to kill purely on skill than just spam all my abilities on everything that moves and because I'm a "nuker" I can kill everyone even in 1v3.
Also, turret's pattern are despicable to learn going as a newbie on the game. They just make their own rules as you play.
I can't say Dota 2 will remain in my laptop's HDD for much time. I could use the space for far more worthwhile experiences, maybe Heroes of the Storm.