Re: Cape Dory or Tartan
Any older boat is suspect to have soft spots. I don't think anyone makes a solid fiberglass deck on a keel boat, it would be to heavy. There are some foam cores out there, but they still get water in them and will delaminate. It boils down to maintenance. Has the hardware been properly bedded? Have any through deck holes been properly sealed? Some factories were better than others, though I don't think there would be an inherent problem with either of these makers. Also owners sometimes add holes, that are not done correctly.
Both boats are going to have a loyal following, so resale should be good, though I would likely give the CD a bit of an advantage here. But neither is likely to appreciate and resale is should not be a major concern with a boat. My logic in an old boat is that I likely will be the last owner unless I am willing to give it away, or have a truly bristol condition boat. There are so many old fiberglass boats out there unless yours is truly stand out they just take for ever to sell and you never get what you think you should.
Both boats are going to be fairly slow, but hey it is sailing not like you need to be in a hurry, unless you want to race.
My guess is that the Tartan would likely have an advantage in light winds, but the CD would likely be more stable in a blow.
The A4 is a good reliable motor that seems to go for ever, but it is gas, so that is a concern for some. It really depends on maintenance. The A4 would be cheaper to replace than just about any diesel.
I think you should buy the one in better shape if you love it. If you don't love it then keep looking.