Recs.
Updated
SpecsUpdate
Pros
Pro Largest diversity of champions with unique play styles
Having 144 champions League of Legends ought to offer the greatest diversity, and it delivers.
Many champions have long combos that need precision in positioning and timings on par with fighting games, while others can be effective without combos at all.
Also, many champions feel really unique (not necessarily complicated) in play style, unseen in other MOBAs.
Cons
Con Takes a long time just to learn the game
If you want to get in the game as a new player, you'll have to play for at least a year, or put in hours and hours of studying just to be able to keep up with what characters do what, and what items to get for which character in any given situation. If you take a few months off from the game and return, you will probably have to relearn the whole game again. Almost every Champion is different, not just in stats, but in mechanics and gameplay altogether, from their original launch. The item shop is changing quite frequently, making you have to relearn it every so many months.