Something very minor, but I have Firefox 3.6.6 in the {Drive}\PortableApps\FirefoxPortable folder and Firefox 4.0 B1 in {Drive}\PortableApps\FirefoxPortableTest folder and they both show up as "Mozilla Firefox, Portable Edition".
For now, easy enough to workaround: hover mouse over both to see which one is which.
It was left off the appinfo.ini in the 4.0 b1 release. You can right-click and rename it
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