Unfortunately it doesn't seem to matter if facing rear or forward as we have two cars with seats facing different ways and he is the same in both. I agree that he may not be comfy at times like Limeslice suggested but it can't be all the time can it? The two seats are quite different in position but he stills cries after 20mins in each of them. If anything, he is a little better in rear facing (more reclined) seat, but only marginally. I hate car trips!
Thanks for your input/suggestions.