As Don L pointed out, it depends on the number of people you intend to have regularly on the boat.
We are a couple who occasionally have one other couple or one of our adult kids
along. So we wanted an aft berth large enough for another couple to sleep comfortably. When we have more than 4 adults for an overnight, we have the salon
settees that are great.
On our Sabre
425 the aft berth is a queen and the bulkhead extends beyond the center line so it takes up about 5/8th of the width of the boat aft. The outside storage locker is big enough for one additional sail and a rolled up dinghy
The queen aft is great underway and at anchor
, though we get a little stern slap on occasion.
We wouldn't trade
the locker for another berth as likely all the stuff we have in the locker would wind
up on the berth anyway.