My angle of attack
If I was in your position I would look at it this way. First, the 27 does not have the 6 foot headroom advertised except under the companion way hatch (personal problem for me). So if this is important go with the 30. There are also the added features to the 30 such as the shower Gary mentioned. If this is not important than the 27 ought to be in the mix.Second, with boats of this maturity it would, for me, really depend on the condition of the individual craft. All those things you hear about on this site are concerns. I would put on paper an objective survey of all features (there are good books for this)and pay for expertise where I did not have confidence. Big ticket items, hull, engine to propeller, mast, etc. would make it a non starter unless you really love to do that sort of work. Rigging from chainplates up is also costly if there are extensive problems. The hatches and ports, if orignal, are past the life expectency as are the sails. Roller furling, galley stuff, PFDs, dock lines, batteries, fenders, get a catalog and add up these costs.I can testify that the 27 is a good boat and I have every reason to believe that the 30 is the same (although the chain plate location bothers me). You should be able to find a dream if you are careful enough to avoid a headache. A buck's worth of being critical will save you 10 bucks in real money. Also your life may depend on it.Andy