Wow! What a great place! The apartment is right in the dead center of all the main attractions and best districts in Rome.
You can't beat going downstairs, walking 10 steps, and then having dinner at a zagat-rated hole-in-the wall Italian restaurant with an impossibly good menu and a vibe that is second to none.
Not to mention...walk another two minutes and you're at the Pantheon where you can enjoy a glass of wine or an Aperol spritz at one of the many plaza cafes.
If you don't mind walking, this is the best area you can stay because of how central it is to everything. We walked to literally every attraction from the flat. Of course, on our GPS we logged 29 miles in four days but we hit absolutely everything there was to see. If you're not as inclined to walk that much, metro and taxi transportation are simple like in the rest of Europe.
The place itself was great. It had a kitchen, refrigerator (which we stocked with food from a market 5 minutes away), cozy heating, comfortable bed, and a good clean bathroom with fresh towels.
Marco was great and we had a very simple pick up and drop off of the keys.
I would definitely fight to get this place again next time I go to Rome.