18 is stamped on the magazines but they actually hold 19.
The best thing to do is read here: CZ-SP01, Shadow, Tactical, etc
I have an SP-01 and I love it. It is large and heavy especially when loaded. It is also very, very accurate, more accurate than both of my Sigs. The weight helps make fast follow-up shots too. There are also plenty of upgrade parts available, though not locally available. Do not let the CZ brand name scare you away, they make excellent high quality products. Like you I am not a big fan of plastic pistols. I like the feel, weight, and stiffness of steel. You can get an SP-01 with a decocker or a manual safety, so you can pick your own flavor. I want to carry my SP-01 concealed next winter, if I can find a holster maker that has an SP-01 mold and is accepting orders.
I would have some reserves about buying one for my wife without her handling it first. The grip is large and combined with the heavy weight may not be the best thing for her. You may have problems reaching the trigger, which can be replaced, and the other controls.