Always consider the boats that are still in production. There is a reason why Hunter and Catalina are still being built today while some of the others are not. Also, you will get better customer service from a manufacturer that is still around today versus one that went out 20 years ago.
The implication being that the best product survived while the inferior ones fell by the wayside? I hope that's not what you're saying. To digress, there were several manufactures now defunct that produced outstanding boats that are still considered superior to the boats you mention. I can think of a half dozen immediately off the top of my head. Customer service? Unless you're at the factory, manufacturers and brokers hire out local contractors to do their repair and commissioning. The same labor pool is available to anyone regardless of the age or manufacturer of their boat.