I spent the week-end here. Location is very good: Literally across from the forum, a 5-10 minute, naturally historically charged, walk to both the Circo Massimo and the Colosseum. Even more important: about 15 minutes away from the Trastevere's incredible neighborhood and restaurants.
A tip: get a room facing the garden: much quieter. Plus, there's something very sweet about flinging open the windows to see orange and olive trees, a fountain with a statue of - who else in an nicely restored Franciscan monastery - but Saint Francis looking over a fountain with gold fish and a nice garden with olive, lemon, and orange trees.
4 star hotel, but the staff were 5 star.
Breakfast was generous, tasty and included.
Value for money: Great.
I've not visited other hotels in Rome, but recommend KHR without hesitation.