band 12 is very rare.
I found out this lte version:
GSM: 850/900/1800/1900 (B2/3/5/8)
WCDMA: 850/900/1900/2100 (B1/2/5/8);
by the way is a specialized android POC (push to talk over cellular)
I understand band 17 is not useful for lte.
Are other better than previous not lte device?
The google Nexus 5X and the Nexus 6P as well as the Pixel's.
If it isn't a Tmobile branded phone it will be hard to find With all that said i would hold off buying a phone till
the newest 600mhz band is turned on.