Ady, your point is valid, but I like the inherently automatic nature of repositories.
At this stage, I'm still in the experimenting stage, and it's possible anyway, I just end up with the default repositories.
* EDIT *
It isn't very nice to post a new reply yet again, so I'll edit instead.
Tried the whole sid thing again from scratch, this time I used aptitude from terminal rather than the built-in updater (and also didn't cancel grub update).
First round was "aptitude safe-upgrade" which grabbed most of the updates.
Than "aptitude full-upgrade" to make sure everything is updated.
All without any noticeable problems.
However, I soon discovered (as clearly stated here - http://wiki.debian.org/ATIProprietary
), that the xserver-xorg-core was too ahead of the AMD driver, so the latter won't install without a downgrade.
Considering I didn't want to go this way, but needed the driver (mostly in order to keep the fan down, seems like it's always on with the open source driver), I will most likely not go the sid way as a permanent solution.
This leaves me with default LMDE or tracking testing, and since between those two the difference is lees obvious than with unstable, I just might stick to default LMDE.
On a more general note, I took a quick look at the Ubuntu repository, and it seems that for the most part, the major packages are up-to-date, so perhaps the regular Mint is the solution after all (not at all that concerned regarding the non-rolling upgrade).
Oh, and of course "I want the latest packages!" isn't the sole guiding line as to what direction to go