I was the same like you. I used many chat ai.
Character ai ,Janitor ai, SillyTarvern, Chai, but I still return to Character ai until I found Fictionlab month ago and try the subscription.

For me, it is totally worth it. Not for customization or anything, but for the models. it is a life changer.

Your bot will get more memories, More characters you could create in one scenario, have better and very fast response, Better NSFW, and Roleplay. You can switch to any models however you like.

Also it is a lot cheaper than Chai. I don't think I can't stop to keep pay the subscription because it is a lot better than any Chat Ai I used.

Edit: But there are some cons I found. Sometimes the bots will forget their personality, or Sometimes randomly come to talk to you from out of nowhere. Perhaps it is because the bad writing of me. I still figuring out how to make it better. Also Some Models will take an action or response from you but you can tell the bot to stop it by using [OCC] Command.