I have experience with 3 of the boats, the S2 being the odd one out. We chartered a Pearson 31 for a week a few years ago, and liked it very much. The downside was the V-berth was too short for me, and I'm only 5' 10". Literally, my toes were jammed up at the end. Otherwise that boat would have been on our "list". We did put the Pearson 33-2 on our list though because we liked the 31.
The Catalina 30 is a great buy. It's the largest of the 3 (not sure about the S2). There are many around, and parts/sails/etc are all easy to find. You can still get help from Catalina. The quality is not as nice as the Sabre or the Pearson, and I don't think they sail as nicely either, but you can't argue with the bang for the buck. We didn't add this boat to our list. It's not a bad boat, just not what my wife and I wanted.
The Sabre 30 Mk III was on our list. As was the Sabre 32 and the Sabre 34 Mk I. They are all very similar in size and layout (with some variations for the 32). We decided we'd buy the first boat on our list that we could find in great condition (which was most important to us). We ended up with the S34-I. Coincidentally, we bought it in Essex, CT.
The Sabres sail very well, are nicely balanced and look pretty to my eye. The build quality is very good for a production builder, and Sabre still will help you out with some support. Obviously, I'm biased as a Sabre owner.
If it were me, I'd focus on the Sabre or the Pearson (if the V-berth is OK for you). But condition should still always win out over a particular model, in my opinion. A Sabre in poor condition is not as good as a top condition Catalina.
Hope this helps!
-J