We just got back from a 4 night stay at Hotel Arenula.
Location was great. Largo Argentina a two minute walk away, from there a short walk to Piazza Navona for dinner and Campo de´Fiori for drinks afterwards. From there Pantheon and the Trevi is in walking distance.
In the other direction from the hotel is Colloseo, approx. a 20 min. walk. If you don´t wanna walk you can catch the bus at Largo Argentina.
Staff was very friendly and helpful with tips about where to go, distances etc. We found both the receptionists, breakfast staff and the maid very friendly. Breakfast was good.
The room was ok. Small and in no way extravagant. But it was clean and effective. The bed was very good. However, the room was not cleaned even once during our stay. We got new towels, the garbage was taken out and the room were tidyed - but not cleaned. I found this kinda odd, bot not a problem. I don´t wash my bathroom and bedroom at home every day, so why should I need this done when I´m at a hotel?
The only really downside I can think of is the stairs. There is no lift in this building, and the stairs were unnormally heavy to walk in. No problem for us, we´re joung and healty, but if you´re elderly or in bad shape I would remomend to request a room on the first floor.
All in all, not a luxurious stay, but a great city hotel.