I've used Goodreads in the past but I've ultimately settled for StoryGraph. I find it has a nice and easy to use interface, and I love that I can get little graphics with data.

I can relate. There's a love/hate relationship with finishing a good book for me, because when I'm done I kind of have to mourn the book and characters, and wanting to know what will happen to them long term, and even just the thought of knowing that rereading the book will never be like the first time I read it lol