I have only played with InterMapper a couple of times, but my network achitect loves it. It is very simple to install and configure. And the price-performance really stood out back when we bought. Best of all, it is Mac only so we got to tell the CIO (since fired) and watch his face turn purple. I have never used the OSX version, which I believe is still in beta, and thus a free download.
You can thank good people at Dartmouth U. for this one. Sadly, it is proprietary.