Machine will be the campus Wiki; reliability would be nice. Performance on sub-par hardware would also be very nice. I don't know much about the differences other than Ext3 isn't a journaling file system, and Mr. Reiser tends to brag alot about how good his filesystem is.
Did some random googling around, but this is another one of those "opinions are like assholes" moments - and I'd rather take an opinion from the IWTGM than from Google.