Foxit Reader Portable
Full user review
"Great PDF Reader - And a Great alternative!"
Windows 8 compatible. Has all the features of its competitor and looks nicer and easier to use. It has a contents, chapters pane with the ability to bookmark places - which you can hide. It effortlessly allows for page scrolling and does what CNet's review said it does. It is much more lightweight than the other one.
For me there isn't any with the Reader itself. But I didn't like the 'Registration' option which required way too many details.
Foxit Reader is a good and just as worthy alternative. After trying a few I knew I'd end up with this one as the others simply lacked too many features. The Registration is geared much more towards Business users I believe. Foxit Reader Portable is compatible with Windows 8, works well and is much better than Win8's own Reader so Foxit has been set to Default. Try it.