After a 5 hour period yesterday upgrading the OS on an HP Series 800 server, which included loading software from 5 different CD's, installing so many patches that i lost count, rebuilding the kernel and rebooting three times (20 ^%@#$^% minutes each), I think it's fair to compare the difference between the platforms as "never having to upgrade the OS". Mainly because if you told someone it took 10 minutes work (on the high end) and 30 seconds of downtime (that most NFS clients don't even know happened) in order to upgrade the OS on a *major* file server, they would think you were totally full of shit. Remember, he's talking to people who's only experience upgrading an OS is probably the 3 or 4 times they've blown a weekend because Gateway technical support told them they had to reload Windows '95 in order to get their printer to work. ;-)
So, i guess even though it's not 100% accurate, what Dan said is certainly understandable, considering the audience.
Graham