To be really honest, I don't think that Splinterlands is "huge". The only huge NFT game right now is Axie Infinity. Splinterlands is big, and I truly believe that it'll become the next huge one. The game is good, it's actually fun to play, the cards economy is healthy.
I also like Rising Star a lot: the theme is good (everyone loves music), the economy is also healthy, the community is strong and active. I just think that the game lacks more active gameplay (like when you chose your cards every match in Splinterlands); right now, you can figure out the "most optimized" way to play and just repeat it day after day. Given the fact that the game will keep releasing new updates and new mechanics, I believe in it too for the future!