I have a 1988 268DA Sundancer and really like it. If you are into trailering, it's about max for going port to port on the weekends.
The beam is a little narrow because they were meant to be trailered without permits. The narrow beam with the deep cut "v" makes them wallow a little side to side, but they are really not bad.
The 270 is about the same length, but a 10ft beam and more difficult to trailer.
My 268 has great sleeping space for overnighting the family, yet fishes great and handles big waves well. It's a great compromise for family and fishing and trailerability to various ports. I'm 6'4" and have plenty of head room down below. Mine has the fridge, kitchenette, dinette, bathroom and aft cabin. It sleeps 5 comfortably.
I have the 330hp 454 big block and she's got plenty of power. The big block or twin 4.3ltrs is the way to go. Do not get the 268 with the small block. Not enough power or rear weight. These boats need rear weight to keep the bow up.
Get a moisture meter and take it with you when you look at these boats. Lots of them have wet transoms/stringers. Check them about 10 inches either side of the transom bracket from the inside of the boat, then check the engine stringers. They will all have some sort of water intrusion, but try to find one that is below 25% on the meter. After buying my boat, I took the motor out and rebuilt the transom and stringer system all the way up to mid-ship. She's a tank now, but she was pretty wet before.
Here are some pics of my rig:
New engine room after the glass work:
Catching 30lb salmon!
Buying a Cruiser for Lake Michigan 
