Only if your time has no value. With at least one day to setup (according to the poster) and issues popping up from time to time (not to mention OS upgrades), the difference is not that big.
We are not even factoring the resale value after a couple years, of an iMac vs a generic hackintosh.
Well the resale argument doesn't really apply to a hackintosh - I wouldn't need to sell it - not at least in 5 years or so - I can just keep upgrading. And a 5 yr old iMac will fetch you roughly $200 from Gazelle.
About time - I suspect more than a handful of people will find spending a day here and there worthwhile if it saves them $400 + $169. (Also if in best case Apple keeps your iMac for 2-3 days in repair - that's time lost as well. You could do the Hackintosh repair faster yourself.)
The OS upgrades however - yeah they will be a pain. I can see that as a significant deterrent.
My greatest deterrent is the OS upgrade. I've been mulling over whether to just buy a Mac, or to build a Hackintosh. I would like the upgrade ability, but I would also prefer to not have to worry about accidentally upgrading my OS and having a few hour downtime every so often.
We are not even factoring the resale value after a couple years, of an iMac vs a generic hackintosh.