Newb here, what's the difference between Dota, HoN, LoL and Dota 2?

I'm completely new to this type of game, I mainly play Team Fortress, Counter Strike, that sort of thing. What exactly is the difference between all of these different ones? I just got a Dota 2 key (no idea how), and am downloading it. My friends all play LoL, and want me to join them. Why should I choose Dota 2 over LoL? For the sake of equality, assume that my friends all have copies of Dota 2. What are the merits of each of these games, and why should I choose Dota 2? You're a salesperson, trying to sell me Dota 2 instead of your competitor, who is selling LoL.