If you are looking for the advantages of a city centre hotel with the tranquillity of being outside the town then this is your hotel. This is a spa hotel with its own grounds on the Gianacolo hill so this comes at a price but...
The hotel is a leisurely three minute walk downhill to the Principe Amadeo bridge and on to the Corso Vittorio Emanuele (take a short cut through the hotel car park) so the major sights are really only minutes away. We were there four days and didn't need to take a taxi or public transport once.
The Vatican is less than ten minutes away. This time you need to take a short cut through the Gianacolo hill car park (which also has a cheap non-touristic coffee shop in the entrance), across the road from the hotel, and down the escalators to St. Peter's square. Another ten minutes walk gets you to the San Pietro railway station if you feel like taking a train somewhere.
The rooms at the hotel are new, spacious and bright, with two ample wardrobes, although no drawer space and the bathrooms well fitted and everything spotlessly clean. Our bath was a bit awkward to get in and out of and would be difficult for someone short or with a bad leg and the lights take a while to figure out, but I'd still give ten out of ten for the room. Breakfast is fine. If you want eggs you'll need to order but the cold buffet is adequate with warm pastries, fruit, cold meats and cheeses etc. and the coffee excellent (as you would expect). The staff were friendly, helpful and looked happy. I must say the Gran Melia hand on heart greeting makes me giggle every time I see it, but if it makes the marketing department happy...
In all I would thoroughly recommend this hotel for a stay in the eternal city. We had blue skies for our four days in November and might not have enjoyed crossing the bridge so much in the freezing cold and driving rain but it really is a great location.

Combining the physical form and structure of a large modern hotel into one of the most architecturally sensitive settings in the world (adjoining the Tiber and the walls of the Vatican), and at the same time providing accommodation of the highest standard, is an achievement in its own right. However, when these physical aspects are combined with the highest standard of customer care within an ambience which is luxurious, unpretentious and homely is all too rare in present day hotel catering. The Gran Melia model has set the standard which will assure the future of this brand for years to come.

The room we were allocated was modern, impeccably clean and well-furnished and equipped: in particular the bed was one of the most comfortable experienced in years of world travel. Where this hotel excels, is in the attention to detail and in particular the quality of staff all of whom were efficient, professional and above all friendly, helpful and welcoming. It is evident that the management and in particular Maria, the Guest Relations Manager, place a high value on customer care and this ethos is evident throughout the hotel. If all Gran Melia Hotels reflect the same values as Hotel Gran Melia Rome Villa Agrippina, I would have little hesitation in choosing this chain above all others.

Took my girlfriend here for a nice weekend away and this place is well worth the money!

Great staff, great location, can walk anywhere from here!

Room was awesome and it was generally a really nice place to stay would go back

Stayed there for three nights, highly recommend this hotel, staff really nice and helpfull, locationis great , beside all best places to see. Real 5 star hotel
If you visit restaurants in surrounding area, be carefull, waiting staff will try to overcharge you, happened to me twice