I'd rather pay the 'extra' money to a PaaS in order to not have to a) hire a sysadmin, or pretend to be one on TV. b) get a full nights sleep. c) be able to go on vacation without worrying if the server is up or not. d) not have to worry about adding servers when my traffic has spiked and this one server isn't enough.
If you don't think EC2 instances go down, you are kidding yourself. Not only do they go down, but they 'appear' up. Talk about a mixed message. So, you also need to pay for a third party monitoring service just to tell you that your server is down.
At the end of the day, when you've added up all of those 'costs' of running your own servers, PaaS starts to look at lot more attractive. I certainly trust a company like Google AppEngine to be able to hire a lot more sysadmins, setup better monitoring and have better response times for fixing servers than I ever could.
I'd also love to never have to learn or remember the arcane list of setup configuration that this person blogged about. Instead, I'd rather be adding features to my app and making money.