Yes, I'm almost half tempted myself, but it's the incompatibility with other software that is dissuading. I think I'll wait until such time as I upgrade my PC. If it ain't broke...
OEM versions come with no retail packaging, and are strictly only intended for use by system builders. Indeed, I believe that part of the deal is that the purchaser of the OEM software is obliged to offer support to the end user, but if purchasing for yourself, this obviously wouldn't be an issue, and there seems to be no stipulation on Ebuyer as to who can purchase the items.