Here's a vote for PrimoPDF:
http://www.primopdf.com/
I don't know about the others, but PrimoPDF allows you to append multiple files together, creating one large file.
I'm in the process of creating PDFs of all of my scripts and scores for electronic transfer. I can string all of the numbers in each show into one file, consecutively numbered, adding title and index pages from a word processor first.
Good luck.
David