Question about using Verizon iPhone 5 on T-Mobile or AT&T

[JayZJay]

My wife bought an iPhone 5 from Verizon in September 2012 on the day that it was able to be pre-ordered.  My understanding is that this phone has worked on T-Mobile, AT&T, and other GSM networks from the beginning due to being GSM unlocked.  However, whereas the Verizon iPhone 5 model (A1429) is geared towards working on Verizon & Sprint's CDMA networks and certain LTE bands, my understanding is that the Verizon iPhone 5 does not support some of the 4G/LTE bands used by T-Mobile, AT&T, and other GSM networks such as UTMS 1700 and LTE bands 2, 4, and 17.

Is my understanding correct as far as the "facts"?  Is there anything that I am overlooking or need to be aware of?

My wife is planning on getting one of the iPhone 6 models that are released and might switch to T-Mobile.  She would like give the iPhone 5 to our daughter to use on T-Mobile as well, if she switches to T-Mobile.  I just want to make sure that my wife's Verizon iPhone 5 can be used on T-Mobile.  Does anyone have experience or insight that they can share?

Thanks in advance for the insight, feedback, and help.

 

-JayZJay

[adrynalyne]

You can see the bands here:

 

http://support.apple.com/kb/SP655

[BoDEAN]

my old iphone 5 on VZW worked when I put a T-Mobile sim in it.