icedowl, do a clean install if you can.
The problems you are hearing about are very small considering the scale(millions) of Win7 upgrades that go without a hitch vs a small number of glitches(thousands).
So proceed with caution - unistall all AV/AS software(reinstall it later), back up important data, make a boot disk and go ahead with the upgrade.
I have not had a problem yet(upgrades I did myself), err on the side of caution if you are that concerned.
I work at a retail store(long story) and am making my rounds as PCs are piling up for the upgrade, most just because the customer is now afraid to do the work themselves because of something they read on the internet.
I am not an MS cheerleader or anything, but the anti-MS bloggers are really running away with this one. I make my living on the web and from PCs, 80% running Windows.* the rest *nix.
I have as many crisis situations on both OSs.......
Don't heed the call of the haters, upgrade if you wish.