Rather than rate the company, as everyone below is doing, I'll rate the actual product: I personally find it best-in-class for this kind of software, and I have used pretty much all of them. iClip is fairly close, but it irritates me by not responding to double-click on a copied item to paste it; you have to click on a tiny little arrow icon instead. With iClipboard you just double-click it.
The only reason this isn't 5 stars is that the app is fairly unstable. I sometimes have it crash multiple times per day (though sometimes it also runs all week without dying). However, I haven't found iClipboard, PTHPasteboard, ClipBuddy, etc., to be any more stable.
I'm sorry that there's some kind of problem right now in getting the 6.0 version (a quick search shows it on at least one BT site, if you're willing to go that route), but I already downloaded it, and it works very well for me. I tend to agree with complaints below that, as just a bug-fix release, it should have been free (and been 5.something, not 6.0, since it added no new features). Same goes for it suddenly not being available from the author's site, after people have paid for it (we often need to re-download and re-install things).
But that's nothing to do with how good this is as a piece of software, and it's darned good. I had a utility like this way back in the day under MacOS 9, and really missed it when making the jump to OS X, and had missed it every single day until I started using iClipboard, back around version 3 or whenever it was that I first found it.