We had a great 4 night stay in Testaccio at Lia's lovely apartment. Couldn't fault it! We loved the area - lots of good places to eat (though a few which Lia had recommended were closed for holidays because it was August) including Da Remo for pizza and the great wine bar in Piazza di Testaccio. Also excellent & very reasonable bakery/patisserie at the end of the road on the corner of the main road (DaFornaio's I think). Testaccio market (2 mins walk) is also brilliant and was one of the main reasons I booked Lia's apartment; I've been reading an excellent food column by Rachel Roddy (who lives in this area) in The Guardian every Saturday for a few years now and always thought she made it sound interesting and worth a visit and I wasn't disappointed. It's also within fairly easy walking distance of central Rome: when we were there it was exceptionally hot and if it's hot when you visit, then I'd strongly recommend making the effort to leave the apartment at c7.30 and walk, eg to the Pantheon or the Colosseum - both are about 25 mins walk. Which reminds me, it was also great to have air con in Lia's apartment - being English, we're not used to 42 degrees!