What are some alternatives?
When comparing PDFTK Builder and PDF-Shuffler, you can also consider the following products
PDFsam - PDFsam Basic, a free, open source, multi-platform software designed to split, merge, extract pages, mix and rotate PDF files
Adobe Acrobat DC - Make your job easier with Adobe Acrobat DC, the trusted PDF creator. Use Acrobat to convert, edit and sign PDF files at your desk or on the go.
PDFill - Open, View, Edit, Save and Print PDF Documents without Adobe Acrobat
iSafePDF - iSafePDF is a free open source PDF protection software.
PDF-XChange Editor - The smallest, fastest, most feature-rich PDF editor/viewer available
UnityPDF - UnityPDF lets you merge, split, divide, rotate, protect PDF files and more.