I got the original Canon hood for the lens. Like most Canon hoods, it features flocking inside the hood (feels like furry material) to help absorb reflections. Cheap copies are hard plastic and more reflective. Due to the wide angle nature of the lens, hoods are not really that effective on it for flare prevention. If that is the main reason for getting one, I'd suggest not even bothering. If you want something to help with protection, then just get the cheapest one.
_________________Canon DSLRs: 7D, 5D2, 1D, 600D, 450D full spectrum, 300D IR mod
Lenses: EF 35/2, 50/1.8, 85/1.8, 135/2+SF, 28-80 V, 70-300L, 100-400L, TS-E 24/3.5L, MP-E 65, EF-S 15-85 IS
3rd party: Zeiss 2/50 makro, Samyang 8mm fisheye, Sigma 150 macro, 120-300 f/2.8 OS, Celestron 1325/13
Tinies: Sony HX9V.