Fantastic location. Noise really wasn't a big problem for us though there was the occasional drunken reveler or root from a motorist in the early hours the rest of the time it was nice and quiet.
15 min stroll from the Vatican. We bought a 72 hour transport pass and used it a grand total of 5 times including to and from the train station making it a waste of money in the end.
Tonatello in Trastevere has some of the freshest Carbonara we've ever tasted. Forgot the name of the bar in Trastevere but for a bit of colourful drinking you can find a place that sells "porno shots" for 1 Euro and cheap happy hour until 10pm.