The official one is very similar to the OEM one, the material of the OEM one is slightly different apparently and obviously the N1 version is slightly taller in size.
Other than that online pics posted comparing both look identical (see my pics in the case thread for OEM pics).
I have 3 of these cases now, my dad nicked one, I have one on mine and one in the car as spare. All 3 look/feel the same and look like a retail product you'd get with the phone itself.
I have had the non Android robot printed OEM neoprone one before and those ones feel mediocre compared to the android printed ones.