Incorrect. The kernel devs specifically cited the quality of the drivers when adding it to the taint list. Check the mailing list if you don't believe me.
The number of bug reports we get from people with virtualbox loaded are
truly astonishing. It's GPL, but sadly that doesn't mean it's good.
Nearly all of these bugs look like random corruption. (corrupt linked lists,
corrupt page tables, and just plain 'weird' crashes).
And the no-GUI, geared-towards-commandline, doesn't-have-directories-with-spaces type stuff is just my personal preference, as I've already said.
This is also bad information. Kernel taint is a bitmap that
represents a number of things:
- Proprietary software (non-gpl-compatible, as you say. ex: vmware)
- Crap (drivers/staging)
- Out-of-tree modules (virtualbox)
- whether the kernel has hit a BUG already
- ...
- lots of stuff
VirtualBox taints the kernel because it is out-of-tree, not because it is GPL-incompatible. Why is a GPL compatible kernel module(s) not merged yet?
Your kernel is tainted whenever you insert non-GPL-compatible modules, it has nothing to do with the quality of the software.
VirtualBox is perfectly usable without the GUI.