You are right to go crazy over this choice but in 20 year old boats, the real choice will come down to the individual vessel unless you want to restrict yourself to looking for one specific model and then try to find one in the condition you want.
If your sailing style is tweaking everything and trying to make the boat go as fast as possible and you want a well built, good looking boat then the Sabre is probably the right boat and it is family friendly but I would absolutely worry about the core before I put my $$ down on one.
On the other hand, if you take longer trips with the family, prefer a more kindly motion to speed, like the flexibility of a cutter
rig and don't want to run out of water in remote anchorages, then the Caliber is probably the best choice.
Have you and your spouse been aboard both boats?? My guess is that ultimately it will come down to spouse approval factor
so that would be where I'd start! Both nice cruising boats with different attributes.