I would've given this place 4 stars because it's modern, clean, moderate amount of space, helpful…read morestaff, free breakfast and free parking. BUT it's location is a bit sketchy at night, the free parking lot is least to be desired however they do have a garage parking for €5 per night (I've already spent enough on this trip, I tried saving anyway I can). The free breakfast well, do yourself a favor, skip it. They do make you free and fresh espresso, cappuccinos so kudos for that. But the breakfast itself... Eggs were so weird, I think it's powdered eggs, undercooked bacon (if and when they had any), canned fruits, and very little selection of food items.
So the good parts? Yes, there are... Modern decor, spacious (for an Italian hotel) rooms, clean, comfy beds (for Italian standard). There is a supermarket Auschan next door but they don't sell cooked food, go here if you want to buy bottled water, snacks, chocolates, Any grocery items. Look for a place called Da Marco for the best pizza in Rome =).
TIP: if you plan to stay here, DO NOT book your hotel via 3rd party sites, for some reason they tack on additional charges of about €30 more. Go directly on the HI site. Also, upon check out, you will be charged an additional €6 per person for some "Rome tax" this is on top of what you already paid for the room. Another tip: utilize their free parking, just take all your belongings with you.
Enjoy!