No need for another PDF reader if you transition to. The MHT files can be written or read on Mac OS too. Internet Explorer comes able to read MHT files 'out of the box', so support for MHT reading is ubiquitous as long as the otherwise annoying IE keeps being installed with the Windows OS. This is a good way cross-platform way to archive web pages. FF displays them just fine, and the HTML links remain working too. MHT files look just like web pages, but without some unneeded MetaData and all the info is squished into a single file-no subfolders needed. MHT files seem to be slightly more sophisticated and simpler to use than PDF files which are quite bloated with metaData. Update it with the UnMHT add-on and it becomes a nice.

I don't use FF portable for online browsing. Remember, lots of different users of differing technical abilities use portable software, and most of them won't manually code a batch file to clean things up. Additionally, crash logs contain personal data, so while you may not care, I think most users would be uncomfortable with some of their personal data left behind on some random PC. Just because the handful of extensions you use don't break doesn't mean that lots of others do, particularly when a new version of Firefox is released and extension X isn't listed as compatible in its manifest but is actually compatible so lets your install of Firefox know. And Mozilla sends folks our way when they want a portable version of Firefox to distribute on USB drives. We negotiated a license to use the Firefox trademarks. If you request a portable version of Firefox, ours is as official as it gets. They don't document or support it as a 'portable' implementation as it is not designed to be used as such.

Well, if that's not enough for you, Mozilla calls the -profile switch a way to point to a specific profile.

Firefox portable install