The extra width of 135mm hubs is normally just to allow for disc brake rotor mounts, no? So, if you're using disc brakes, 135mm. If it's a normal road hub it'll almost certainly be 130mm, even if it's 11-speed compatible (though it sounds like the new 11-speed Shimano standard is 131mm).
In any case, the wider the hub flanges are spaced apart, the stronger the wheel will be, so that's the key factor if there's no requirement for discs.
@Regal
The extra width of 135mm hubs is normally just to allow for disc brake rotor mounts, no? So, if you're using disc brakes, 135mm. If it's a normal road hub it'll almost certainly be 130mm, even if it's 11-speed compatible (though it sounds like the new 11-speed Shimano standard is 131mm).
In any case, the wider the hub flanges are spaced apart, the stronger the wheel will be, so that's the key factor if there's no requirement for discs.