We spent 3 nights at this hotel in March 2009 and we would definitely return here in the future (that is if what they say about Trevi'c coin tossing was true, of course :) Firstly, the location is great. Even though there are probably cheaper and more numerous hotels in Termini area aimed at budget travelers, I'm very glad we chose the Prati area. The subway is at about 15 minutes walk on a quiet and real Roman neighborhood (hardly any tourists there, which is awesomely peaceful when returning home in the evenings, after being intoxicated with camera flashes and noisy high school kids all day long...)
The front desk staff is helpful enough and they make you feel you can approach them on any problem you might have. The room we got was quite large for European standards, decorated with pictures from the times when the building was an aristocratic point, while the bathroom was on the same level of appreciation. The only downside is that the breakfast room is quite small, but given the fact that there are only about 30 rooms in the hotel, congestion wasn't really a problem. Breakfast was ok, don't expect too much meat and cheese though - there's mostly sweet stuff , croissants and eggs. Nevertheless, you can absolutely get your fill for about 4-5 hours of walking and visiting.
All in all, choosing hotel Delle Vittorie was a small "vittoria" for us (vs Termini creepy area) and we highly recommend it for all type of travelers.