LSFR

I found this Free Spanish flashcard tool web app thing thats super fun and has like all the references I need,, i was thinking about getting the Premium right now i'm just on Free but idk yet has anyone else tried it? i want to know if its worth it to upgrade because i dont really like the structure of DuoLingo or some of the others i feel like i can learn faster this way and hell i might just stay on the free version of this xD
https://learnspanishforreal.com/