ZEB B I've used PTH Pasteboard for several years. I've tried most of the alternatives, including the free ones. PTH Pasteboard more than the others gets the right amount screen space, but not too much-it's configurable; shows enough of the clips to be useful, also configurable (and pops up more if you hover); and offers the most options for pasting. The Pro version was worth the investment to me: I wanted the ability to exclude sensitive information and some of the text-processing filters can be a time saver, compared to going to TextSoap. There are many options for configuring size, window appearance, and where the windows will open. On the negative side, with too many extra pasteboards, it's easy to forget which menubar symbol opens which. I find it easier to memorize the hotkeys.
All in all it's a solid product.
(Version 4.5.2)