Great location so close to the Colosseum and metro. We had no issues checking in and no issues using the keys - we had two sets. The AC was excellent and quiet. The kitchen is tight but clean and looks new. Great to have use of a washing machine. The gift pack of clothes detergent was welcome. Excellent and fast WiFi. Bed was clean and comfortable.
The road is busy (it is five minutes from the Colosseum, so not unexpected) and therefore noisy and we had to use earplugs to sleep, even with the windows closed. There are a couple of nice restaurants in the same street and a supermarket one street away.
We had issues with a blocked toilet (fixed after two days of a three day stay) and the bathroom was not clean on our arrival. We were fortunate that friends were staying five mins down the road and we were able to use their bathroom for two days.
We also had the same issue with leaving the keys i.e., you need the keys to operate the lift, then have to leave the keys in the flat on departure. You don't need the keys to exit the building: there is a button on the inside of the ground floor locked stairwell to allow you to exit without a key. You do the the keys to enter the stairwell (same as other flats in Rome). We were fortunate that there were two of use to allow one person the take the luggage down in the lift (which is tiny - one person and one suitcase size) whilst the other kept the door to the flat open.
Check the ammenities before the check in person leaves. We suggest IFlat invest in a safe dropbox near the street door or inside the locked stairwell to save you multiple trips either up four flights of stairs or in the lift on departure.