Pros and Cons of using a Broker
I have always liked the Sabre 28''s and 28 footers in general. 28 feet is big enough to have a fair amount of seaworthiness and deal with anything that would normally come at you and yet small enough to be handy to sail short handed (as in two adults trying to keep an eye on the boat and an eye on 3 young kids.
The Sabres are a little better built than many of the higher production boats of their size and offer pretty reasonable performance on for a boat of that era(performance should be pretty comparable to a Catalina 27 but the Sabre is a much better built boat). Mike is right that these are not great light air boats but they are not terrible either.
A couple feet of addition length certainly would make a significant difference in performance and comfort. If you did go to 30 feet the Tartan 30 has always been a favorite of mine. The Pearson 30 is another very nice sailing boat. I have never been a fan of the C&C 30 but prefer the somewhat faster and better proportioned C&C 29.
Obviously, as with any 20 year old boat a good servey is crucial.