I realized I couldn't do an apartment rental review on TA, so thought I'd post it here. My husband and I rented the "Balestrari" apartment through Sleep in Italy for 4 nights in early May.
Sleep in Italy was great, answered our emails promptly. You pay them a deposit and then you have to pay the balance in cash upon arrival (the downside of renting an apt). The owner met us at the apartment and showed us around. He was very nice, and we had no issues at all, so we didn't need to contact him again.
Overall, I highly recommend this apartment and highly recommend renting an apartment in Rome. We loved the experience of feeling like we lived there! The cost is very reasonable compared to a hotel in the same area and you have a lot more space.
The location was Amazing!! We loved the area, there were so many restaurants and bars nearby and it was very centrally located. The closest transportation is the bus from Largo Argentina. We took bus #60 to the Vatican and to Termini (opposite directions). Those two times were the only times we needed transportation, the rest of the time we walked. Oh, but we did take a cab from the airport and it was really convenient since we didn't know where we were going.
We ate dinner in the neighborhood at Al Balestrari (directly across the street from the apartment - shortest commute ever) which was great, we went back twice. Good food for a reasonable price. We also went to Ar Galletto in Piazza Farnese also a nice place. Another night we went to da Pancrazio (a block from the apt) and the food was outstanding but the service wasn't friendly. For breakfast we found a "bar" about a block away where we'd get pastries a caffe latte and an Orange Juice and stand at the counter to eat.
The apartment had plenty of space, especially for two people. There were two bedrooms but we didn't even go in the other bedroom. The bed is large and pretty comfortable. There are dressers, etc if you want to unpack. There is a dining table and a small love seat in the main room along with a TV. They had pretty much everything you'd need in the kitchen, plus an iron, hair dryer and more. There were plenty of towels too. The washer worked well, but since it was raining while we were there (and no dryer in the apt) we took our clothes to dry at a laundromat about a block away.
The only potential downsides: it is two flights of stairs up (no elevator), there was a little bit of noise from outside although it didn't wake us up or anything (you're far enough off the square not to hear the noise there) and the shower was small and a little moldy. Also, there is no daily maid service, not that anyone would expect that. Remember to bring everything like soap, laundry detergent, lotion, etc. None of that is provided.
I did a google map and marked everything I referenced above. Please let me know if you have any questions!