The Lumia ICON is the only Windows Phone from Verizon that supports the new XLTE:
http://www.wpcentral.com/these-windows-phones-take-advantage-verizon-xlte
What is XLTE:
http://www.wpcentral.com/verizon-flips-switch-700-mhz-enhanced-xlte
Is your city getting XLTE from Verizon:
Here are Verizon's initial XLTE cities | Windows Phone Central
According to the official list reposted at WP Central, the Samsung Ativ SE is also XLTE-ready right now. The Lumia 928 is expected to get a firmware update to support XLTE as well. The 928 has the necessary hardware but it's not enabled. I don't know if the HTC 8X has the necessary support for XLTE.
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