I have a 43' Ocean and they are somewhat notorious for poor following sea performance. A combination of narrow transom relative to mid-ship beam, small keel and flat aft section built for speed are all reasons I've heard. Interestingly, I find the handling in following/quartering seas much worse with small wakes in otherwise flat water. If I get caught with one of those while the bow is trimmed down, the boat can do some pretty surprising rolling and yawing. Her nose will get pushed down by the swell and want to bow steer. In bigger seas the motion is not great but not nearly as crazy. And I don't get caught by surprise by prevailing sea conditions so I know not to be trimmed down. On my boat I've learned that in following seas, I remove all trim tab and get the ass of the boat to sit down. I play with the speed to match the swell as best as possible. And I generally have much better handling with the AP ON. Unless I'm in a narrow channel or for a brief period of time, I'm better off with the AP steering.