I would recommend Clips over most other clipboard managers I've tried. I use Typinator (a great text expander), but it can't handle complex formats. Thus, I was looking for a program that would manage formated clips; that is, tables and combinations of text, tables, and images especially from the Pages word processing program (though Clips can work with all other programs too). In this regard I've tried iClips, Shadowclipboard, and Clipboard Evolved, but feel Clips is the best and is more robust than the others. I've seen some people comment on cost, but you get what you pay for...
One of the best features of Clips is that you can assign an abbreviation to any of your clips that will then automatically paste itself, works much like a text expander. For example, I have a large table I made in Pages and copied it into Clips. I then assigned the abbrevation "pheader" to it. Now whenever I want to paste this into a Pages document, I just type "pheader" and instantly it appears. I have abrevations for all my formated clips and is a great time saver. Clips (like other managers) also offers keyboard shortcuts, but I find these less helpful and less intuitive. Again, I know text expander programs use abrevations, but they can't handle the type of formats I needed.
The user interface is nice and very iTunes-like. I feel it is somewhat more user friendly vs the others, but this is subjective.
When using the program, just remember to turn off clipboard monitoring after you have copied what you want, or you end up with lots of clips you have to eventually delete.
One last comment for powerusers is that this abbrevation function brings up many interesting possibilities if you know how to use Applescript.