Hi surface2air

wind + swell in same direction = bigger waves

The question was which situation produces bigger waves. Not which are cleaner. I agree that the wind in opposing direction can make for a cleaner wave and hence better for surfing. Wind and waves in the same direction, particularly when blowing directly into the beach can certainly chop things up. If were just looking at the size of the swell, the swell will be higher when the wind moves with it.