I own and sailed a 1976 Catalina 22 for four years (my brother-in-law is using the boat now). It had a swing keel. The draft with the keel down is five feet, which is pretty deep for a 22-foot boat. I have previously posted regarding how I came by this boat, but that is not relevant. If I were purchasing a C-22 today, I would get the fixed wing keel. The reason would be much less maintenance.
(If anyone can describe this better, have at it.) The swing keel attaches to the hull by means of a bar that is bolted into the bottom of the boat, and it pivots up and down on this bar. There is a winch just inside the companion way below the cockpit that houses a steel cable that attaches to the trailing edge of the keel near the bottom. The keel is raised and lowered by the winch and cable combination. The cable exits (or enters) the boat through a molded fiberglass "cone" that is part of the bottom of the boat. The top of the cone contains a ball into which a pin is inserted to keep it in place. All of this is covered by a foot-long piece of radiator hose that is held in place on the cone by a hose clamp. One also puts some sealer around the bottom of the hose. This is to keep entering the boat. I have seen the cone described as a "volcano" and the water does flow out like lava if the hose is loose.
I replaced the winch once and the cable twice in four years. I finally learned to keep the cable taut instead of with some slack, as the slack can cause it to "whip," become abraded, and snap. When the cable snaps the keel is in the "down" position, which is OK for sailing (unless you are in a shallow slip) but may present some problems getting it on and off the trailer. You can only replace the cable when the boat is out of the water.
You have none of this with a fixed keel. Of course, you also get a 3.5-foot draft with the wing, so this may affect performance.
Getting the boat on and off the trailer is not the biggest issue you have. The biggest issue is raising and lowering the mast each time you launch and haul out. The fore stay and at least two of the shrouds had to be detached to lower the mast and reattached to raise it. The 22 had a device that one could buy that allegedly allowed one person to raise and lower. I did it with one other person and found that three people are better. Two can raise the mast but you need the third person to attach and do the other things to secure the mast while the others are holding it steady.
As far as which boat is better for day sailing and short trips, I can't really say. The 25 is three feet longer and thus the berthing arrangement is probably a little better than the 22. The 22 has a small V-berth and two singles in the main cabin, but is very cramped.
There is a Catalina owners web site, www.catalinaowners.com
, as well as e-mail lists for the various Catalina models. Current owners should be able to answer any questions you have on these two boats.