It's HSPA+, which is HSUPA and HSDPA combined, and somehow it results in a ceiling of 21MBps download, 5.76Mbps upload, those speeds cannot be actually reached, but either way, the HSDPA that phones have had for years were rated with a ceiling of 7.2, so this is faster on paper as a start. (I guess you could say 3x faster than just 7.2 HSDPA).
I think it will be faster again once LTE is rolled out In America?