Pros: The flat is in a great location- less than a 5 minute walk to the Vatican (Sistene Chapel, museum, St Peters Basilica, etc.). There are lots of great restaurants and only about 10 minute walk to the metro. We walked to the Colisium, Pantheon, etc but it was a bit far for our younger kids (10 &12 and it was also 93 degrees), but it was very do-able. Make sure you purchase tickets in advance- makes it so much easier. We had plenty of space with a nice patio.
Cons: The place needs a deep cleaning. The beds were good but everything else needed scrubbed. We were site seeing the whole time so we weren't there except to sleep but it definitly bothered us.