I have a 2005 2520SL, with a Yamaha F250. Notched transom. It has a slightly smaller pilothouse than the XL, however I like the port bench in the SL better than the XL seating arrangement. Also, while the XL has a larger pilothouse, it has a narrower \\\"walkaround\\\" area to the front of the boat. The cockpit is larger on the SL (see pics of my boat in my link below).
I like the SL quite alot. The Yamaha F250 is defintely worth it if your marina has 89 octane gas. No issues whatsoever with water over the transom, although I go out on calmer days than some here, I imagine.
Regarding safety... one school says a closed transom with bracket is safer, as it is tougher for a large wave to swamp the boat, and one school says a notched transom is better because a large wave that would swamp the XL or the SL would drain quicker on the SL with the notched transom. I don't have an opinion on the matter, except to say that if you see a large wave, insist politely that it avoids your boat :lol: .