Aft Berth
The big difference I see is the aft berth. On the 240 it is perpendicular to the boat which would make the first one in even more claustrophobic than on the 23.5. The 240 has tubular support struts for raising the mast, seems like more trouble to store or to replace. The 23.5 has a slight bit more sail area not sure if this translates into being faster or not. We were looking at both when we bought our 23.5 sitting right next to each other there was not much difference. Sounds like the 23.5 with the price difference is the way to go. The only thing on the 240 we looked at I liked better was the stern rail seats, which I have added and the cloth interior which I am now glad we do not have.