What's your favourite PDF editing/annotation app?

Nick Pawsey has been using PDF Expert:
here's some news about the latest features.

See these YouTube demos on PDF Expert:

• a simple run-through
• Opening PDFs from your email 
• Integrating PDF Expert and Dropbox

This review compares PDF Expert 4, iAnnotate 2.1 and GoodReader 3

Most reviews of PDF expert are about the full-size iPad.
If you've used it, how do you find it on the Mini?

Do you have a PDF app to recommend?