We already had the Tom Cat when we went from the 22 to the 25 (we kept a second C Dory on the West Coast). Our major reason was the bunk size, and ease of access, plus a bit more room in navigator's seat--storage, and the head. For us, it was a better fit. I single handed launched the boat behind a 30 foot RV, so launching was not a problem. The ride is better--but not as good as the Tom Cat--which has the ride of the others out paced by a mile...On the otherhand, the 25, will do better at lower speeds than the Tom Cat. In either of the 22 or 25's if you get 3 foot seas, you will be slowing down--in our case 1.5 feet because of back issues--the Tom Cat goes over them until into the 3' chop plus.
We had about 4 miles a gallon with a 2 stroke on our 22, and 2.3 with the 25. We get almost the same with the Tom Cat. I agree with Tyboo about the engine--we had the 130, and after some prop changes it was OK--but I would have rather had a 150. Be sure and get trim tabs AND a Permatrim on either of the C Dories--it does give a better ride.