Tux Guitar comes to mind but some things like chord diagrams isn’t done as well as guitar pro (imo).
For chord diagrams (like at the top of GP), there’s hundreds of websites out there which show those and its probably quicker to just use those. I’ll usually just search “C chord <instrument>”.
It’s an alright service, I just wish they would have used/merged the same login for CBC and Radio-Canada content instead of 2 different sites with 2 different logins.
As for premium, I would also have preferred that they removed the ads in the “live feeds”. I’d be fine with it just being a screen with the CBC logo and the text “Ad Break”.
At least the pricing (6$ for Gem) seems fair.