I have to be honest and say I have not stayed at the Hotel Locarno...but not because I didn't try. I booked a reservation with the hotel 3 weeks prior to my vacation in Italy. Upon checking in I was informed that the hotel was overbooked and that there was not a room available for my fiance' and me. Although I was exhausted from several hours of travel that day, I smiled at the woman at the front desk and told her I understood, that sometimes these things just happen. She informed me that they had booked us at a comparable hotel, located just down the street. I thanked her and waited for the offer of a taxi to our new hotel. It never came...and the new hotel was not down the street, it was a few miles away, and up the Spanish Steps - not too convenient when you have 2 heavy bags. If you choose to stay at this hotel I would strongly recommend confirming your reservation several times.

A friend, as well as several travel books including Frommer's, indicated that Locarno was a great "artsy" choice for staying in Roma.
I was concerned about the bad reviews here (as I was correct to be), but wanted to trust my friend and the books, and was excited about the art deco decor. So, I decided to book an expensive room (junior suite) at the hotel, thinking this would alleviate some of the issues. On arrival, we were upgraded to the "Presidential Suite" room 603. This is admittedly a huge room, with truly traditional (and by traditional, I mean likely original) decor and furniture.
So what was the problem? Well, there were many.
The bed may actually be 100+ years old. It is flat, hard but bad springs at the same time; and EXTREMELY uncomfortable. Its like a box spring.
The lovely bathroom reeks of sewage smell, and we had to open windows (it was cold outside; I imagine this problem is even worse when it is hot) in order to alleviate the scent (so, we froze in the bathroom and after showers).
The room literally does not have enough light, management must think the little sconces are romantic, but in a huge room, they basically provide no lighting. We couldn't read at night. We could hear our neighbors very clearly in the next room.
I was miserable, still suffering jet lag three nights into our vacation, and had to request six pillows to sleep on to put on top of the "bed". My husband was embarrassed to also do so, but I think would have done well after all of our sightseeing and the ridiculously bad bed. You know the worst bed you have slept on, like your uncle's pull out couch bed from the 70's? This one is worse.
Also, the key to the room is nearly impossible to use. The employee who brought us to the room had trouble with it; and my husband (an engineer) struggled with it throughout our stay. Again, managers may think this is quaint, as it is an "old" original skeleton key, but like the other relics of the room, it is one that should be revised.

All of that said, the location is lovely, and the breakfast is generous and well-done. There is a nice roof deck, although it was too cold in November to enjoy. The bar and common areas are very nice. And, the art deco decor is truly amazing. Overall, the service was decent, but our other Italy stays (in Milan and Venice) were so truly superior, that I just can't give this one a good review. I have to believe that there are much better places to stay in Rome.
If Locarno decides to make some appropriate investments in: plumbing, lighting, bedding and mattresses, as well as superior service actions, and I read about those here, I would consider another stay. But, at this point, I definitely cannot recommend it.

We stayed four nights at the Hotel Locarno and thoroughly enjoyed our stay. The best thing is the location; we were within walking distance to everything - from the Spanish Steps, Trevi Fountain, Pantheon and the Piazza del Poppolo. Everything you needed was close.

The room is small, but then in my experience, most European hotel rooms are...so no surprises there. They were tastefully decorated with antiques and the housekeeping staff was very friendly (and English speaking).

The breakfast buffet was wonderful and the staff was very friendly and accommodating.

We would stay at the Hotel Locarno again if/when we get to Rome.

Pretty Hotel downtown Rome, close to Piazza del Popolo, 10 mns walk from Piazza di Spagna.
Ask for room in the central block (possibly not in the dependance opposite the street).
Bikes available to visit the city.