The X is HSPA+, the LTE is LTE - the difference is data speed. LTE can download up to 300Mbps while HSPA+ tops out at 42Mbps. Right now, however, on the Rogers network LTE maxes out at 75Mbps and typical will be between 12-25Mbps, while HSPA+ maxes out at 21Mbps & around 7Mbps would be more typical.
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Great video.