In the days before the internet, the WRTH was the go-to book to check frequencies and schedules. However there's a big problem - schedules are now changing fast and furious, and print media simply can't keep up. This, in part, made the various update PDFs that the WRTH has on its website a necessity. That, along with rising publication costs and one or two other things killed off its competitor, Passport to World Band Radio.
In short the internet is a far better resource for SWBC scheds. The SW Info website only uses 1 source - the Aoki database- and if it isn't updated on a regular basis, it too will become out of date. And as any good researcher will tell you, it's dangerous to rely on a single source of information
Are there other lists? Yes, there are the EiBi, HFCC and a few others. Now you can get a spreadsheet that incorporates many of them. You can get it for free from the SWSkeds reflector on groups.io. You can download the spreadsheet so you can have it even if the internet isn't available. You can even get a downloadable file that you can put in some SDRs
You want to stay up to date? Get that spreadsheet and subscribe to a couple of reflectors that regularly report on changes in the HF broadcasting scene. These would be the World of Radio and DX Listening Digest reflectors - I'm sure there are many others.
You can find links for all of this here...
wiki.radioreference.com
Yes, the net is the eventual death of printed publications in this hobby. The WRTH has been able to keep up to a certain degree because it has a standing in the professional world. But sadly it won't last forever...Mike