I personally love the Manzoni neighborhood. It’s lively, youthful, and authentic - but within walking distance of the colosseum and the Palatine. It’s also very close to the Metro, so you can access it from Termini. The apartment is elegant, sparkling clean, with furniture that reflects the architecture. It’s quite spacious as well. The owner was able to secure a cab for my sister to the airport - and they were on time and very courteous. I also appreciated the personal handbook that had very useful information about the area, including great restaurants and where you can get the best gelato in the city!