[Moto X Q&A] KidJoe:
If ATT is using Band 4 for LTE in your area, you'll get it with the Verizon X (using an ATT SIM).

If you are in the other areas where ATT uses their other bands, then no.

The Verizon X will get "4G" HSPA/HSPA+ on ATT.

---------- Post added at 11:45 AM ---------- Previous post was at 11:28 AM ----------

I know its an old post, but since [MENTION=3225038]sunny757[/MENTION] brought it up... I feel I have to...

The Verizon X has different radios due to CDMA/EVDO support. The confusion around Band 4 support was due to the Band 4 support being added with the 4.4 update well after the X had been on sale. Prior to that (4.2.2) the Verizon X only supported LTE Band 13. So many sites listed the initial Band 13 only, and never were updated when Moto and Verizon started pushing 4.4.

Verizon DID update the specs on their page, moto didn't update theirs for the dev edition, so many wrongfully assumed the Dev Edition didn't support Band 4 yet the Retail and Moto Maker version for Verizon did). That lead to confusion around the Verizon Developer Edition X and the Moto Maker or Retail X for Verizon. Yes, they are the same. The only difference is the casing (woven white back, black front, silver accent is the only choice on the Dev Edition), the Dev Ed is only available as 32gig, and the fact that Moto gives out the Bootloader unlock code on their web site for the Verizon Developer Edition, where they don't for the other Verizon models. The Dev and Moto Maker variants use the same exact XT1060 ROM/SBF/FXZ. (and if you use the China Middleman, you can get the bootloader unlock code for a Moto Maker or retail Verizon X)

Some confusion leading to the multiple answers you are getting is centered around the definition of 4G.

On Verizon, 4G = LTE, as EVDO is 3G, and CDMA/1xRTT is 2G. T-Mobile and ATT call their LTE 4G, but also call HSPA/HSPA+ 4G. and of course UMTS/HSPA is 3G, Edge as 2G (some say 2.5G), etc.

Because the Verizon X supports HSPA/HSPA+ (up to 41mbs download) on the same frequencies ATT uses (and T-Mobile in refarmed areas), you can get 4G HSPA+ when using an ATT SIM in a Verizon X (and a T-Mobile sim if you are in areas where T-Mobile refarmed 1900mhz from Edge to HSPA). So its truthful to say you'll get 4G when using an ATT SIM in a Verizon X. And in some cases a T-Mobile SIM.

Because the Verizon X supports LTE Band 4, and ATT and T-Mobile use Band 4 in some areas, it is possible to get LTE when using either an ATT or T-Mobile sim. However, Band 4 is not ATT's primary LTE band and not used everywhere so there will be many areas where the Verizon X with ATT sim will NOT get LTE, but a few areas it will.

To top it off, unlike the ATT and some other variants, the Verizon X is sim unlocked out of the box. Its due to the FCC rules around the 700mhz C block auction VZW won. Since Verizon bills it as a "Global phone" and doesn't share that you can put domestic sims in it, many wrongfully assume it only works with non-domestic sims. Again, you can stick a T-Mobile, ATT or other GSM carrier SIM card in there and it will work. No need to SIM unlock or unlock any frequencies to use domestically.

So to quote Ben Kenobi, what they told you is true, from a certain point of view.