My son and I decided to take a father/son side trip for 4 days to Rome from Poland in Aug 2014. We took a Wizzair flight for $300 rt each and stayed in a NH hotel near the Vatican and subway station.
Cons:
1 August is really a humid time, locals leave town but probably fewer tourists, you have to eat lots of gelato at the gelato cafes at night
2 The Trevi Fountain, the Boat Fountain at the Spanish Steps are both under renovation.....bummer..it looked like a long term deal
Pros:
1 Carried my Rick Steve's Rome book with me
2 Took advantage of the Roma Pass for free entries for me and my son (under 17) to many sites
3 Went to Rick's recommend eating places each day in the area we were touring and hit homeruns each time
4 Had three separate occasions when random strangers, all claiming to be Canadian from Montreal approached us to converse or sit next to us at lunch pointing out our Rick Steve's book....felt like I was being stalked by Canadians
5. Son wanted to see "bones" in the catacombs, there were none in the catacombs, so we went to a bizarre place called the Crypt of the Capuchin Monks (thanks Rick), where some monk with interior decorating desires decided to use the bones of 4000 monks to decorate various rooms...and name them, The Crypt of the Pelvic Bones, the Crypt of the Shoulder Blades and so on.
Rick's book on Rome paid for itself the first day of the trip.