We fish on overnight trips a few times per year, typically four or five large guys. Owned the boat since 2008. Without a doubt, the aft berth is favored by everyone that ever slept or took a nap in the cabin. You can lean your back against the bulkhead and stay comfortable in most seas regardless of if your trolling, running, anchored or drifting. Two people in the aft berth does not happen often, typically only with family. I'm 6'2" and have no problem getting comfortable down there.
The forward bunks are obviously more open and airy, but the starboard side is a little short for me and unless its flat calm, it is not as comfortable due to being so far forward towards the bow.