Re: Tartan 27 or Tartan 30
Like most posters I agree the T30 is a good choice. I have a T30 but have not sailed a T27. As already mentioned the T30, Yankee 30 and S&S 30 are almost identical boats.
One consideration relates to offshore sailing. The boat is very sturdy, but the cockpit is big, the scuppers are small and there is no bridgedeck. Adding or enlarging the scuppers and glassing in the lower part of the companionway would not be too big a job and would be a good idea to avoid downflooding if you get swamped.