I'm using PDFill PDF Tools
It's fast and allows a lot of things to be done with the PDFs (split, rotate, extraxct images, etc).
What I like best is that I can set a way to crop all the pages and then change the margins for single pages before executing (to for ex. keep the coverpage uncropped)
PS: It does come together with the PDF-Editor (shareware) and as far as I know it cannot be installed/used without it - but there is no need to run or even buy the editor, the tools are free and can be used without limitations.