I’ve just looked at ForScore and I guess, if you need sheet music, it would be pretty good. For those of us that are gigging in rock/blues/country bands and just need chord charts or tabs, lyrics, and setlists, GuitarTapp Pro still seems to be pretty good. A song has to be pretty obscure to not be available on GuitarTapp Pro. I also set mine up with a black screen with white lettering and yellow chords - it’s easier to reference during stage performance (for me anyway). If you need sheet music in order to play, then GuitarTapp is not for you.
I didn’t get a full-on look at ForScore simply because I didn’t want to spend $27.99 CDN for something to replace what I’m already very satisfied with. Plus, for what I do, I don’t ever need sheet music.
I also looked at the MusicNote app, which was free with 5 star reviews. The free library provided is extremely limited, so you have to purchase pretty much everything as you need it. Just for fun, I searched for sheet music for a rock song. Nope. (And I picked a tune that I knew there was sheet music available for)