the issues arent so much with the voodoo kernels themselves but 90 % of problems seem to be in removing it improperly or not removing before trying to odin restore. A lot of people are making a new folder disable_lagfix instead of a new FILE disable_lagfix in the sdcard/voodoo folder when trying to disable it and then flashing stuff on top of that.
Others (like myself) ran into issues when flashing a voodoo kernel that we were getting bombed with fc's on the next boot and forgot to uninstall voodoo before flashing odin. When that happens the phones partition has not been put back to stock so then you are unable to read internal memory and issues arise.
The fc hell seems to be a big one, and many have fixed simply by batt pull, clockwork, fix permissions. While others have had to manually uninstall voodoo and odin back to stock.
Adrynlyne put out a voodoo uninstaller to flash in recovery but is still recommending that people manually uinstall voodoo in recovery with adb by pushing the original mbr.
I tend to think that at some point (although I'm not wishing it on anyone) everyone will run into a similar issue either by making a simple mistake or just bad luck. Once you have ithappen though and you fix its reassuring knowing that what seems like a totally f-ed up phone can be completely fixed by taking a deep breath and repeating your steps to see what you did wrong.
You're a pretty knowledgable user Piiman, so you may easily learn from our mistakes and not have an issue