So paying double or more for the same PC hardware in an "Apple" case. If you really want to run OSX you can without the Apple price tag. Plenty of FAQs out there on how to do it.
I'd rather have
http://pcpartpicker.com/p/tXqJNG :-)
Sure the Dell 27" 5k monitor is $2500 but the prices will drop very quickly when more come to market.
Plus you're not stuck with an all in one which is hard to upgrade. Plus the number of motherboard faults (logic board faults as Apple calls it) I've seen I'll pass :-)