When I moved to the Storygraph I used a Goodreads export. If I remember correctly, I just had to delete some extraneous columns and (maybe?) re-arrange some others. It was certainly worth doing over recreating the data from scratch, and I didn't have 4000 books!

I agree that Goodreads could do better with recommendations, but I keep wishing that Netflix's recommendations would come up to the Goodreads standard.

My list has evolved from paper to Goodreads + a spreadsheet (data redundancy) to Storygraph + spreadsheet.

I dread the day that Storygraph becomes the place to go crap on books you haven't read because you don't like some aspect of the author's politics, which is the primary reason I left Goodreads. At least on the Storygraph the social element is available but feels less in-your-face.

Goodreads still tends to be where I go to read the description, get series info, etc, but I use a fake email when I do.

58 here and have tracked since 2007, so not entirely age-based, but perhaps I'm an exception.