First of all, I hope I posted in the right place...

Second, well, the title says it all. I plan to download a free image viewer that can view those uncommonly used file types at its full featured capability without the "upgrade" hitches. Anyway, my main concern is of course the number of file types it can handle.

But my question is of course for my second concern --- which is the more stable, less buggy, not so invasive (meaning it doesnt make itself the primary image viewer, doesnt conflict with other programs and when you uninstall it doesnt leave residue), faster, and has a simple and non-requirement-heavy interface.

Xnview or Irfanview?

Would like to hear the reasons why and personal experiences if there are any

Thankies

They're both, good programs.
I use both of them, but I do most of my work with Irfanview.

Xnview will Read/Write more file types, so I use it to convert the occasional oddball files, to the more "standard" formats.
Then, I'll use Irfanview, to do most of the image editing, as I find the program easier to use, but that's probably because it was the one I started to use first.

There also seems to be more support for Irfanview, by way of plug-ins, and tutorials.
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I've tried both programs and find Irfanview a lot easier to use for editing imo ;)

Both are good; both are free. Why not download each and see which is easier for you to use?
Regards,
John