Incorrect,the gsm has more bands, below are bands supported by variants of this device.
Network •
*2G/2.5G GSM/GPRS/EDGE:*850/900/1800/1900 MHz
•*3G UMTS/HSPA:
EMEA: 900/1900/2100 MHz with HSPA+ up to*42 Mbps
Asia: 850/900/1900/2100 MHz with HSPA+ up*to 42 Mbps
Sprint: 1900/2100 MHz with HSPA+ up to 14.4*Mbps
Verizon: 850/900/1900/2100 MHz with HSPA+*up to 14.4 Mbps
• 3G CDMA:*Sprint/Verizon: 800/1900 MHz
• 4G LTE:
EMEA: 800/900/1800/2600 MHz
Asia: 900/1800/2100/2600 MHz
Sprint: 1900 MHz
Verizon: 700 MHz
there is no other difference rather than they are locked on just sprint sim ... and sprint guys will unlock it for you for international use for free .. and if you want to unlock it for US then either follow the steps in the unlocking thread for HTC one max or either pay them to unlock your phone
i too have a sprint htc one max By the way .. its on the stock Sprint ROM now ... so there are no major diffrences you will just get few extra bloatware included from sprint in the ROM nothing else