If I could get the Nexus 5 for the US price of $349, I would buy it immediately. Right now. This minute. But, the Nexus 5 is sold in Europe for $550 or even higher,

which makes it just another expensive phone in an array of other expensive phones. The Nexus 5 is priced here the same as Samsung Galaxy S4 or LG G2, annihilating its main perceived advantage: an enticing price-point. It's not that far off, in price, from a veritable phablet like Samsung Galaxy Note 3.
An additional difficulty in purchasing an Android phone, at least in my country, is that it's impossible, difficult or expensive to share your existing data plan between 2 phones. If I could just take turns in using two phones -- using an Android phone on odd days, and using iPhone on even days -- that would be great. Swapping the SIM card itself on a daily basis would be too much hassle. And I'm not quite ready to ditch the iOS ecosystem (mainly due to top-quality 3rd-party apps like Marvin and Mailbox, not available on Android). Again, if the Nexus 5 cost $349 here, I might give it a try. But it being overpriced, along with all these additional difficulties, makes me postpone a purchase for the time being. (Also, rumours about a 5.7-inch "iPhablet" are starting to swirl; that would be something! Though, no doubt, even more heinously overpriced.)