Just got back from 5 days in Rome yesterday. I've been to quite a few places in my time and I have to say Rome is the most fantastic place I have ever been. Beautiful city and my wife and I had a lovely stay.
I understand it gets busier in summer and although we had nice weather it wasnt overly busy.
We managed to visit the Colloseum which was very good, the Pantheon which was fascinating, Spanish steps worth ticking off if you go, Trevi Fountain which is gorgeous and the Vatican Museum and St Peters Basilica both of which are awe inspiring and you have to go to understand. The most opulent m rammed full of history, art, amazing ceilings etc just an amazing place
The city is easy to walk around and with google maps everything easy to find and in quite small location. Every corner you turn almost there is a fountain, sculptures , massive archways just an amazing location.
I've seen mention of smart dress codes and couldnt disagree more. We ate in expensive places, general italian restaurants etc and people just wore smart casual. I wore jeans, trainers, polo t shirt and was probably smarter than some. Its just a city like any other city so I wouldnt bother with dinner jackets and all that nonsense unless you felt the need to.
It was far cheaper than I expected, certainly not as pricy as New York, London, Paris Dublin etc
Food wise , well its Italy so its mostly Italian style restaurants, lots of pizza, pastas, fish and meats too
I felt safe whilst wandering around day or night whilst being careful to keep my wallet safe and watch hidden but generally it seemed fine certainly safer feeling than may cities I have been too.
You will love it