I just stayed there for five nights (on points), and I thought it was spectacular. I have stayed at the Excelsior before, and I thought the SR was better.

I was upgraded to a bedroom which connects to the Bottega Veneta Suite, but is also sold as a seprate bedroom. It was on the top floor, and had a great view of the Piazza della Repubblica. I loved watching the people and the traffic in the circle. You could also see Termini Station and the Baths of Diocletian (turned into a church by Michaelangelo). The room was not large, but it was very light, with a nice bathroom, and high ceilings which probably made it feel bigger than it was. I am guessing it was an upgrade because of the view, and not the size. I think the front desk told me it was an Imperial Room, but I'm not 100% sure.

They have a nice exercise room, and a spa, which can be used for free (no purchae of treatment required). They also have three elevator locations, including the "diplomatic" elevator, and a cage elevator in an open stairwell (which is automated).

The staff was superb, as was the concierge. The rooms were quiet, with blackout shades (which were recessed and I didn't notice until the third day).

I splurged twice on the outrageously expensive breakfast buffet (41 euro), with the rationale that I could skip lunch, and eat more protein for breakfast than just a cappuccino and a croissant.

Others have commented about the location and the neighborhood being undesirable. I thought the location was absolutely fine. It's about a five to six minute walk north of Termini station, and a two or three minute walk north of the Republica Metro stop. Barberini is not too far either. There are plenty of restaurants in the area. It is not close to the Spanish Steps or Via Veneto, but both are easily accessible by subway, and the hotel also sits between two of the major east-west streets where many of the buses run, including the bus to the Vatican, so it's well located for public transportation. I used the Rome Pass for three of my days, and it worked out well.

I stayed at the Excelsior in 2001, and thought this was nicer on the whole, although my room at the Excelsior was larger. I did not care much for the restaurants on the Via Veneto, and the St Regis is better situated for transportation.

My only nit is that they were oddly stingy with bath towels, although if I called for more, the hotel staff always brought them instantly. We showered twice a day because it was so hot, and we were always kind of sweaty when we came in from sightseeing at the end of the day.