I agree, excpet thinking they have decent drive sleds. How do you make a server that lets you accidentally bump a drive and dismount it? Want to have that ejected drive come back online? Gotta reboot the server. Want to use the lock on the box to prevent those drives from accidentally dismounting? Sure you you explicitly picked a boot volume in the Startup Disk control panel, otherwise you'll get that lovely blinking question mark if you ever try to reboot it when locked.
The mounting/hardware of the Xserve lines seems like what you'd come up with if you'd never actually had to deal with servers before.