Our decision was between a shoal keel (3 1/4 foot draft) Hunter 27, and a full keel (5 1/2 foot) Catalina 30. Our marina at the time said they could not guarantee entrance depth of 5 1/2 feet, so we bought the Hunter. We have chartered a Catalina 30 twice out of Anacortes, and know we would have been happy with either design.
In addition to our old marina, the deep draft 30 would keep us out of 2 of our favorite anchorages in our Lake Erie cruising grounds. With a longer water line would cruise a little faster, and the deep keel takes her 10 to 20 degrees closer to the wind. But we are equally content cruising in either boat. We think the 27 has plenty of room for 2. (6 foot cabin clearance) the only issue for the 5 times we have cruised a week with 4 is finding room for baggage.
Maintenance of the 30 will be 20% to 30% more. We have averaged around $1,200 per year over 17 years, so the 30 would have cost us a extra $300 per year. The 30 is heavier, and the load on sail lines is nearly twice as much. So it's easier to manhandle the 27 at the dock, and it's lines under sail, but we had no problem on either issue with the 30.
See the boats. Lie down in the bunks with those you want to sail with you. Make sure you have clearance for your head. Then buy the boat you and yours like!