I would second the recommendation; I owned a C&C 30 for 5 years. While not that large on the inside, she sailed quite well and no maintenance problems to speak of. Mine was built in 1984 and I believe they had switched to a cored hull by then.
A good alternative to the C&C 27 is the late 70''s C&C 26. Although not well known and hard to find, its a great boat. Only slightly slower than a 27 with alot more interior. If you''d like more info email me at [email protected]
Have a C&C27 Mk2. Like other balsa cored decked boats, water penetration can cause problems. Would suggest that they are no better or worse than most other cored decked boats. I have just repaired two minor wet core areas on my boat totalling 1.5 sq.ft. I think that speaks pretty well for a boat built in 1973.The 27''s are superb boats, particularly the MK2 as they are really good sailing coastal cruisers.
Finishing up my first year on a C&C25 mk1 and it has proven to be a wonderful sailboat. Mine was retrofit with an outboard in place of the Vire 7HP gas inboard which has had little effect on the performance and a lot less hassles. Boat is stiff and powers through the chop we get in Buzzards Bay. Had some concern about deck integrity but have taken steps to epoxy any questionable areas. This boat can run down a lot of 30 footers on a beam reach.