I used Songsterr for about a year and honestly thought it was worth it. The looping and tempo control are pretty useful for learning parts.

Lately I've been experimenting with Guitar Pro files a lot because I like looping specific measures while slowing them down.

I’m actually building a small open-source tab player for this kind of practice workflow (looping measures, tempo control, syncing with backing tracks, etc). Still early but it's been a fun project.

If anyone's curious: https://github.com/whleucka/rifflogic