If you want a view of the pantheon, you need to ensure you get a room with a view. It will cost more, tho. Hotel was clean, services friendly, breakfast buffet outstanding; a large variety with some daily changes. Free internet on TV with laptop option.
Room was a bit dusty. bathtub meant for baths and not showers as there is no shower curtain. Plus side: Jacuzzi tub. The hotel's mercedes can take you to the airport for 55E flat, which is nice if you have an early flight. The piazza it sits on is bustling day and night so there is always something open for you to eat or drink. The restaurant directly across from the hotel had the best gellato we had the whole trip, esp the dark chocolate gellato.
We went during early March, so the tourist season was not yet in full swing. I can imagine things being worse around July.

We stayed at the hotel in late April with our two young children. The hotel was located right by the Pantheon -- literally 50 feet away. Even with two children under the age of 6, the location was perfect and we were able to walk everywhere in Roma.

The front desk was helpful and the breakfast was typical small hotel fare. The room was spacious for the four of us, but the only problem was it was extremely hot. Late April was unusually warm in 2008, but they did not turn on the air conditioning until May 1 so naptime for our youngest was very difficult, but by evening it was bearable -- probably 78F or 25C still in our room (hotter than outside).

The room was relatively inexpensive compared to other similar located hotels in Roma.

I would return again.

We stayed one night in the annex room and were very disappointed. The annex is severly in need of a FULL renovation. Old bed covers , miniscule closet bathroom, musty and dusty. Very noisy, even in early Dec. Bed unconfirtable , hard and sqeeky.The view of the Pantheon was great but coulld not make up for the negatives. The front desk receptionist Luigi was arrogant and unhelpful. The breakfast was adequate and the breakfast lady very nice and sweet.I can not see how this can be a 4 star hotel. I can not recommend this hotel.

Stayed here for 3 nights - we had a good view of the Pantheon if we leaned out of the window, otherwise we looked across the Piazza. The piazza is really buzzing, great in Nov. but would be noisy in the summer if you wanted the windows open. The room was v. pleasant but we found the beds hard & the bathroom small, but the breakfasts were excellent - little bowls of fruit salad, scrambled eggs & pancetta on toast, peaches & fresh yoghurt, baked apples with muesli & cinamon, all served in an open-air courtyard in the middle of the hotel (even in November). because of an awning & patio heaters. Although the location is great, it is quite a way from the nearest metro - not a problem if the weather's good or you like walking. We would stay here again because of the location.
We found a great day out of Rome - take the train from termini to Castel Gandolfo, the Pope's summer residence overlooking a huge lake. which is in the crater of a defunct volcano. Next door is a great restaurant, Pagnanelli's, where if you contact them, they will arrange a wine-tasting & give you a tour of the cellars - fantastic.