Others probably have better insight but... A closed transom with a bracket that puts the motors further back makes the boat ride like a larger boat due to the increased length of boat in the water. And you usually get some more storage, although the transom fish box on most older models are not insulated and don't get used as anything more than storage a lot of times. The notched transom can be nice for tucking the motor up closer to the cockpit so you don't struggle to guide a hooked fish around the motors. But depending on the boat and the motor weight you might need to watch for waves following into the boat when you back off the throttle. If the boat is old enough to originally have two stroke engines, then keep in mind the newer four strokes tend to be heavier and might make boat ride a little lower in the water towards the transom.
If you need your 23 to handle waves like a 25 then a bracket might be good. If you can get to your spots pretty quick and the seas aren't too bad then the notched transom might be better.