I also had a nasty experience, made worse with the about 350MB download required. I am running Office 2010 32-bit on two computers--one is Windows-7 32 bit and one is Windows-7 64-bit.
I downloaded the Office 32 bit file from the MS download site onto my 64-bit machine, and burned it onto a CD as a backup. The CD file did install and update my Office 2010 on my Windows-7 32-bit machine. The same CD file did NOT install on my Windows-7 64-bit
machine. I tried using the file original downloaded onto the 64-bit machine. Failure, again. In desperation, I used MS's Update mechanism to automatically download SP2 and install it. It worked.
Why did the update work for my 64-bit machine via the MS update path, but did not work via the MS download path? [Am I correct that the two files for Office 2010--32-bit and 64-bit refers to the version of Office 2010 and NOT to the version of Windows-7 being
used?]
This type of situation should never happen. Both update paths--MS auto update and MS download update should generate identical files and therefore work identically; especially since one wants to make a CD copy of the SP as a backup.