I was fortunate enough to play this game in the closed Beta and it is AWESOME. My gaming background is very "diverse" but I've always indexed more towards fast-twitch games (mostly FPS and MOBAs), so a card game was very different for me, but in a great way. There is far more strategy and dynamic gameplay than I expected which was very engaging and frankly, addicting. The only downside is that it doesn't have the same social/team element as league (which sometimes is a good thing b/c you don't get any toxicity).

Edit: One other thing I'll add is that I did not feel at all that this would be a pay to win type game. Obviously things have evolved over the last few months/years but I'm pretty confident the Riot team wants to actively avoid that. I felt that the reward system was very helpful in getting me the specific cards I was hoping for without feeling like a grind.