if so, what model will work best in USA? Is the appropriate model rootable/unlockable yet?
http://dl-developer.sonymobile.com/documentation/whitepapers/Xperia_Z3_D6603_D6633_D6643_D6653_D6616_WP_1.pdf
D6603
UMTS HSPA+ 850 (Band V), 900 (Band VIII), 1700 (Band IV), 1900 (Band II), 2100 (Band...