Today's downtime (and Sunday's earlier in the week) were the result of electrical problems with our datacenter (Hurricane Electric). Since I also recently de-journaled our /home filesystem (from ext3 to ext2) to improve disk I/O performance, the power cycle forced our machine to perform a very long e2fsck to confirm disk integrity.
Short answer: we should be a good bit faster because of the de-journaling, but when electrical problems like this force a power cycle, we might stay down for a day.
Electrical problems are rare for datacenters and hopefully this won't happen again.