PDF Shaper is an easy-to-use tool for converting PDF files to RTF.
The program is lightweight and should run on just about any PC (it supports Windows NT - 8, both 32 and 64-bit).
But it also offers plenty of conversion tools, with support for converting text, tables and images, numbered and bulleted lists, several types of font encoding, and more.
PDF Shaper is very simple to use. Specify one or more files to convert, give it a destination file or folder, click Convert - and that's it. All you then have to do is watch the status window as it reports conversion progress (and you won't even be doing that for long, as the program is fairly quick).
How does it perform? Our results were mixed. Simple text formatting was reproduced well. We weren't so lucky with images, though - some appeared, but others were only partly displayed (we might see the top half of a picture, say). Tables weren't always formatted correctly, either.