I just started getting into pathfinder 2, and subsequently took a closer look at this site. While it certainly LOOKS the best, there is some missing functionality in the filtering. You can filter multiple things with and/or, but you cannot say “include these, but not those”.
Here is a specific example: I would like to see the spells that are ONLY in both arcane and divine traditions. So, Daemon Form fits this description since it is in the arcane and divine traditions, but not the primal or occult. There is no way to filter it in this way. you also cannot sort by traditions to group them all together, so you have to just look through the list until you see them.
I’m not sure if I can mention other sites here or not, but there is another site that does this functionality fine. I would, of course, prefer to use this site. One nice thing about this site is that you do not have to load a new page to see the details of items in the list (individual spells in my example). Along those lines, it would also be nice to not have multiple pages of items in the list, and just have one long list. But, I think I know why that may not be feasible.
EDIT: I stand corrected. The other site cannot do this either, although it CAN sort them by tradition, so they are all grouped together.