Ignore everything Arri said and give it a go. :3

Of course people who dislike the MOBA genre will tell you it isn't worth it. If you have played DotA before then you already know what to expect in terms of gameplay and community.

Oh, LoL has an easier learning curve than DotA by the way. Certain mechanics were completely removed and some others were modified to fit a more casual playerbase.

The download size isn't that big anyway, install it, try a few games, and if you feel like it isn't your kind of game proceed to uninstall and forget about it like you mentioned. :P