I am installing a new range with a canopy style hood against an exterior wall. Along the exterior wall there is a large deck, the decking level with the interior floors of the house (same height). I can either vent the hood straight out through the wall or up through the roof. What are the pros and cons?

I'm thinking out the wall would create a blast of smells from cooking inside that might not work well because that area is often used for gathering/sitting. Venting through the roof would still force the air to shoot down towards the deck. I'm concerned about that down air "blasting" into the gutters (only 8' from the decking) and emptying out leaves and debris onto people sitting out on the deck.

Any suggestions?