Where to buy unlocked 5s, model A1457?

See this list

http://www.apple.com/iphone/LTE/

In Europe unlocked iPhones are only available direct from Apple Retail Stores or Apple on line store

The difference would be no warranty support outside the US if you purchase a US iPhone.

The warranty is not and has never been International.

Buy the device in the country where it is intended to be used.

And LTE is not guarantted to function, as well.

diesel vdub wrote:

...

Buy the device in the country where it is intended to be used.

Some people use their phone in multiple countries, but want only one phone.

I think that's what the question is really getting at.

If I wanted a phone for (just picking at random) USA, Germany, Japan and India, and wanted to freely switch between AT&T, T-Mobile, Verizon, and Sprint while in the USA, what would be my best option?

No, most of the people who are posting these questions are trying to get a cheaper iPhone.

You cannot freely switch between Verizon and Sprint, they are CDMA carriers and do not accept carry in phones. You can purchase a Verizon iPhone and use it on AT&T, T-Mobile and other GSM carriers. As others have already said there is no guarantee you will get LTE service and you will have to return ot the US for warranty service.

cwebber1 wrote:

If I wanted a phone to freely switch between AT&T, T-Mobile, Verizon, and Sprint while in the USA, what would be my best option?

There is option.

Sprint and Verizon will only activate devices on their network that were specifically sold for their network. You cannot activate an AT&T or unlocked iPhone on either of those networks.