Which is a Better Home Base in Rome?

I liked Trastevere because it seems less crowded, more like a neighborhood. We spent 6 nights there last October. We were able to walk to the Vatican (about 30-40 minutes), a bus line and taxi stand were within a couple of blocks and walked to the Borghese Gallery (long walk). When we went to a more central area it was shocking how crowded it was compared to Trastevere. We were also close to many churches, restaurants and grocery stores. We found our lodging on cross-pollinate.com.

I don't know about Gianicolo.

Well, one is closer to the Vatican, and one is Tiber Island. The good and bad news is that there is no wrong answer so it comes down to personal choice. Both are good options. Personally I prefer the the Trastevere neighborhood as some of my favorite restaurants are in that area. The walking distance also isn't all that great between them either.

To me it depends a lot on transportation options. The Gianicolo area is lovely, residential, and it can be a short (15 minute?) walk to Trastevere, depending on exactly where you are. Is there a bus nearby? Handy for coming home at the end of the day.

Trastevere is a huge neighborhood. Are you looking at places more or less near the Ponte di Sisto, as opposed to down south by the train station? If so, you'll probably enjoy Trastevere more than Gianicolo, which is too sleepy and out of the way for my tastes.

Thanks everyone for your input! Very helpful. This will be my first time to Rome and my first time using AirBnB. And I'm just basing everything on the photographs that I'm seeing online, so it's been a bit difficult.

Keep in mind that many of those photos are taken with a lens that makes the rooms look larger than they actually are. Also, if you can get an actual address, be sure to use Google Maps Streetview to check out the immediate area for yourself. Be advised: There is graffiti almost everywhere in Rome. It is an Italian word, after all. Don't let it put you off.