In the past, I knew of Gelateria Navona, just a few doors up from the actual piazza, and that was…read moremy go-to place for gelato in Rome. Expecting it to be there one year, I walked over to Piazza Navona and Gelateria Navona had evidently closed. I would then get gelato here and there.
I then learned that Giolitti is a long standing gelateria and it's also in the historic center. I filed the name away in my head. Then, one day, I happened to walk right in front of it without even looking for it, so I went in.
Giolitti is popular and it can be crowded. I'm going to say that I waited about 10 to 15 minutes. You pay at a counter first, deciding on what you want and how much of it, such as scoops and whether it will be in a cup or a cone. Once up at the counter, they don't rush you, which surprised me. I don't take that much time since I don't experiment much, but I still appreciate the courtesy. The price is roughly what everyone else in the historic center is charging.
I always opt for the gelato it in a cup so you can "control" the dripping. The gelato - a mix of dark chocolate and two citrus flavors - was "molto buono." That said, just because it's so popular, I'm not going to downgrade Giolitti for it and complain about the crowds. You downgrade gourmet donut places in the U.S. where their fame has gone to their heads. There is also a spacious salon with nicer decor in which you can eat inside. At this point, Giolitti is really the only gelateria in Rome whose name I remember. I would gladly go back and I recommend it.