Been going to Cittas regularly since they opened and agree that it’s quaint, friendly and very very good Italian food. However, they’re back home in Italy for a few weeks and will probably be closed when you go (that’s if you can even get in without booking). They originally owned Cibos in Pontcanna and you can get essentially the same menu at Cibos, which is arguably a nicer environment (and an indoor toilet…). It’s a short walk up Cathedral Rd. Alternatively, another good Italian is Casanova opposite the entrance to the Millennium stadium. I also agree with Potted Pig. Great food and can be a good “underground” atmosphere if the right crowd are in. With regard to chains, Miller & Carter do reliably good steaks and Jamies can be good. If you have time during the day, check out Pettigrews tearooms for a good old fashioned afternoon tea (set into the castle wall next to the bridge over the Taff. Depending on the time of your visit, you could catch the water taxi by Pettigrews down to the bay, where there a number of chain places to eat, but better choice of quality in town. If it’s a Friday and you like Jazz, there’s usually great Jazz and tapas at the fabulous college of music and drama behind the castle, although check dates to see if they’ve restarted sessions after Xmas. Avoid Caroline St unless you like chips. And chicken. And curry sauce – that’s unless it’s the wee hours and you need sustenance to soak up the beer.
It’s a fantastic city. You’ll love it. PS Barkers coffee shop near to where you’re staying (same arcade as Madame Fromage) and Garlands in the arcade opposite the castle (I think Duke St arcade) are good for coffee (Barkers) and lunch (Garlands). For chain coffee, #1 Coffee (owned by Brains) are very good too. The brewery quarter has choice, but not quality. Bistrot Pierre is the best of a very mediocre bunch in the 1/4 in my opinion (your views may vary etc)
Molgrips is probably referring to the purple poppadum and it is very good. You should also consider The Clink next to the prison. Cast away all of your preconceptions about the concept of food cooked by inmates because the food is very very good and not at all what you’d expect. Seriously.