I wouldn't call it 99% accurate; it mentions several very old (2014) feeds on 87 Ku that are long gone.
All the satellite chart websites that I know are struggling to be kept up to date, and each has its own positive and negative points:
- Lyngsat is quite clear and easy to read, but is a bit slow on the updates at least for the Americas
- SatHint seems to be a bit behind on updates and has some duplicate satellites
- SatBeams is great for the maps, but almost useless at this point for the charts for the Americas. Probably quite good for Europe though
- PortalEDS is probably the best for those satellites that cover South American and that we can get from here. It's in Portuguese and in Spanish but that's not really a problem.
- Tvrosat is very good at updating the charts for C-Band for the main satellites visible form the US/Canada. The focus is clearly on C-Band though, and it's missing a lot of charts, notably in Ku band satellites (it lists only 3 transponders on 97W Ku!)
In the end, I monitor Lyngsat, tvrosat and portalEDS for updates. None of them are perfect, but all are useful.