Just a very quick $.02 worth on this one...
The Opanda has worked great for me but I wasn't able to get Kuso to work with Firefox (or IE or Netscape). It works fine as a stand alone but not with my browsers. Also, I couldn't find any support for Kuso either...at least not in English (lots of pretty little Asian symbols that while very decorative, don't really mean a lot of you don't understand the language). I really don't know if the problem is because I'm only runny Windows 2K or if it's a hardware issue or a browser issue or what, but I would suggest going with Opanda for most folks to avoid any problems.
Many thanks out to Bob for posting the link!