I also switched from a WD 120gig HD to a Maxtor. The main reason for this was that, after all the trouble I went through to get my system silent, the HD ended up being the loudest component. So I bought myself a Maxtor 200gig, which used an FDB motor. VERY big difference in sound compared to the WD !! I was most pleased.
Unfortunately, the Maxtor died about 40 days later. No warning, just dead. I had backupped about 90% of my data, but still lost some important stuff. Grrr. This was the third time this happened to me with Maxtor, and I can guarantee you it will also be the last time.
WD has finally announced some FDB drives too now, so with a bit of luck, I'll then have the opportunity to get a lot of diskspace that is relieable AND silent too. (WD has never given me any trouble - so far...)

I've just been playing with the onboard "Acoustic Management" features of the drive, and there is a dramatic difference in noise levels

I know. I haven't used the acoustic management software from Maxtor (and probably never will now ), but I have used the software from IBM on an IBM/Hitachi drive. You're right, the difference is really big, and for someone who really only uses his PC to write texts and surf the net and for whom HD speed thus isn't THAT important (I guess that's the same group of people who would like to have their PC silent), it comes highly recommended !