The Arrow 5 thumb compass is not suitable for orienteering. The compass needle jams against the base of the compass. The axis pin on which the needle pivots is allowed to move laterlly, allowing the needle to contact the base of the compass.
A quick shake is all that is required to free the needle, but the compass requires frequent shakings in order to get accurate readings.
Suunto sent me the Arrow 5 thumb compass after I returned my Arrow 1 thumb compass on warranty after my compass developed an air bubble inside the casing. The Arrow 1 thumb compass, before the air bubble formed, performed much better than the Arrow 5.
I've had the good luck to use the Moscow thumb compass during orienteering meets. It has a fast settling needle. It's a good orienteering compass at a relatively good price.