Which PDF reader searches 4000+ page documents the fastest?

I have a several large textbooks in PDF format that I regularly search through using the PDF reader's find function.

Skim on OS X is my preferred reader, but searching a large text like Harrison's can take a minute or more for each occurrence. Every time you hit enter, it starts the crawl from your current cursor point.

Preview, on the other hand, continues to search after it finds a hit and then lists the results on the side pane. Vastly better interface.

Do you guys know of a better PDF search workflow?

My ideal system would be a combination of Preview's search and Spotlight. Given a bucket of large PDFs, show me all the pages, regardless of which PDF they came from, with occurrences by rank.