I just played my first few LoL games today, this is what it's like.
Im an average casual white male, who's never played league of legends. I just installed it on my pc and played 3 games; this is my experience.
If you are brand new, you basically have a hero pool of about 8 heroes to choose from. In addition to your standard four spells you can also choose 2 spells that make you ungankable, (you can choose a heal, a phase boots like ability, a slow etc)
Every hero has a huge mana pool so everyone just spams spells which do little damage. The spell effects are also lackluster even the ultimates.
On a side note, if you are an average player in hon, you will be a god in LoL. I went 15-0-15 in all 3 games.
TL;DR LoL is a fun game because you can dominate 12 year olds and its free, but it will never be as good as hon.