-Walther P99: Never fired one
-Taurus 24/7: Never fired one
-CZ75B: Probably the most naturally-pointing, ergonomic, and just plain comfortable gun I've ever held. The DA pull is great (better than a SIG, IMO) and the SA pull is pretty good. DA trigger reach is long, and I have big hands. Recoil is pretty light. This is great, good-lucking, and fun-to-shoot gun. I have tried out three of these (range rentals) and all had some issues with stovepiping, which leads me to believe that they will start acting up if not cleaned regularly. All in all, this is next gun I want to buy.
-Springfield XD: A very unpleasant gun to shoot. Comfortable to hold, points naturally, but the recoil is fierce for 9 mm. This gun, for whatever reason, felt like it was trying to jump out of my hand. You also get a nice stinging sensation through the grip with each shot. I really wanted to like this gun, and it seems like a ton of gun for the price, but I just couldn't warm up to it.
-Beretta PX4: This gun is unbelievably easy to shoot. Points naturally, although the grip is somewhat thick. Trigger reach is reasonable in DA. DA pull is great, SA pull has some take-up but a crisp break. Very little muzzle flip, very soft shooting; this gun shoots more softly than a 92FS. Incidentally, this is gun I bought.
I've had only FTF with my PX4 in over 800 rounds--a HydraShok, and the gun was pretty dirty at the time. If you want a DA/SA, I don't think you can go wrong with the PX4.