Concetta is definitely considered dated in Italy. Not many people nowadays use it. I personally find most Italian Marian names to be ugly and dated, but this one more so than the others.
I don't particularly care for this name, but I don't hate it either. It's a little too frilly for my tastes.
I go to school with a Concetta, the second oldest daughter of a large Italian family, and she's in many of my classes. Every time we have a substitute teacher, her name is always mispronounced, so keep that in mind if you are considering naming a child this.
There's a girl in one of my classes named Concetta, who goes by Connie. Considering that we're both of Italian descent, I'm surprised I hadn't heard the name before. It's pretty.
A "C" before an "O" always makes a hard "K". In this case, pronounce the "O" as in "Oh, My Dear!". "C" before "E" makes "Che", which is almost a soft "Chay" sound. Pronounce both "TT"s, most easily accomplished by placing a bit extra emphasis on the letter before (Etta). "A" as is in "Father". [noted -ed]