What is Reddit's opinion of Spellbook - Pathfinder?

From 3.5 billion Reddit comments

I'm using Spellbook - Pathfinder (I think it's a paid app but I'm unable to see the price) in tandem with Pathfinder Spellbook.

Apps generally allow you to only have one thing open at a time, not being tabbed, so several spell apps are beneficial to me in general.
However, the one I linked allows you to build "spellbooks" for your characters. You can even add cross-class spells in case you get them somehow, which the usual by-class listing of most apps won't provide.

I only wish it would also allow me to track prepared spells and available/expended spell slots, but I guess you can't have everything.