[rcxdude]

It's very similar but often faster. The Odroid U2 uses removable EMMC storage which has an SD card adaptor, which I feel is a very good middle ground (most of the advantages of both with the disadvantage that the connector on the board is non-standard).

[tomswartz07]

SD cards have different classes- without seeing specs, I'd be willing to bet that a Class 10 SDhc card is on par with this EMMC storage.

[bronson]

Correct, plus the cheap SD connectors are a source of a lot of noise and unreliability. Just doing away with them will be a huge benefit.