I have been using it for some time now, and likewise find it excellent for PDF files, okay, it may not have all the whistles and bells that Acrobat may have, but lets face it, probably 99.9% of the time all we want to do is read a document.
And as you say, Fast, Small and runs from the folder which I find strange because it's still found when clicking on a PDF file. Maybe it's in the registry from the first time it's looked at?
Thanks for the reminder as newcomers may not see or find the original recommendation from Chris.