My perception (finger in the air) is that we are being given around 95% uptime (down ~8.5 hrs per week for upgrades and unscheduled maintenance). It would be good to know how stable the servers actually are over time.
From my past MMO experience, WoW generally had 1hr a week of downtime which is closer to 99.5% uptime.
Thoughts? Just me that cares about this kind of information?