I'm trying to grasp your definition of "mid-sized" pistol.
You exclude "full size" and "compact" models. Since there are some "full size" guns with 4-inch barrels as well as 5-inch barrels the mid-size term begs for more definition. For instance, I wouldn't consider the Browning HP to be "mid-sized".
My votes for a "mid-size" pistol (my definition) are as follows:
Colt 9mm Combat Commander
The steel frame of the Colt really dampens recoil making it easy to return to target. It's the familiar 1911 pattern, only the hole in the barrel is smaller. Especially good for those used to carrying the .45 version and have lots of time vested in the 1911 platform.
Slightly smaller but much lighter at 26oz is the
S&W Model 39-series (39-2, 439, 549, 39xx).
S&W Model 39-2, 8+1 9mm pistol
The aluminum alloy frame, steel slide, curved backstrap and decent sights make this a fun gun to shoot. This single-stack pistol is very reliable and became nearly bullet-proof in the -2 and later models. These guns are essentially a Walther P-38 action in an Americanized pistol configuration. The P-38 was noted for its ruggedness and reliability and the S&W pistols are similar. They are also accurate, but not match-target accuracy.
The CZ-P01 gets my nod as a very good mid-sized pistol. It's dimensions make it well balanced and good in the hand, with no bulky feeling. The P01 has a good following and is on a short-list of desireable "next purchases".