The best things about NitroPDF Reader are the speed and the highly compatible drag'n'drop capability - it seems to handle pretty much anything from Office docs and templates including Excel, though not PPT (I assume this is because I have MSOffice installed - YMMV) to webpages and images, even icon files - a desktop.ini, file, even. It even displayed all the frames of a 1.4Mb gif of the phases of the moon. But if it can't open a PSD for example, it doesn't make a fuss, the error dialog isn't the usual patronizing nonsense(!). It's also pretty fast - the big test is the 72Mb 452-page full-colour 'Lomax's Cowboy Songs' from the Internet Archive. Opening this in Adobe Reader is a trial as Reader tries to generate the pages and thumbnails at once - jumping from page to page at random is impossible.. With Nitro PDF it's still a little sluggish (this with XXClone running btw), but it's smooth enough and at least it doesn't give the appearance of hanging or crashing, and you can navigate at random quite confidently. As another comparison I tried this PDF in Foxit Reader, which again grinds to a virtual halt under the strain of generating page thumbnails you didn't ask for.
You can't create a PDF from scratch, but there's no problem editing an existing text, rtf doc or pdf, and the built-in convert-to-text or image extract functions work as described. A workaround is to create a blank Word document and use that. To add images, just insert ('create new') a signature file from the 'QuickSign' dialog - this doesn't work too well with huge images, btw.
The look is vaguely Office 2007, and the inevitable 'upgrade' adbuttons are quite discreet. The tab function is well implemented.
There's no mousewheel zoom, which would be nice.
They seem to have kept their part of the bargain, though - it's a fast, comprehensive and stable PDF reader and converter with some editing. annotation and collaboration functions which are not difficult to access, and which work intuitively. A keeper.

Re Mousewheel - Ctrl+mousewheel works, sorry:)