This was booked through a well known last momen web site, and has taught me to avoid them (the last moment people) at all costs. We booked an extra night in Rome via our travel guide book, for the same price as our time at the Marcus, and the hotel we booked was a palace in comparison to the Marcus, with the same star rating & handy location.
I think our list of complaints mirrors others here, sheets instead of towels, holes in the walls for some eccentric pluming and wiring, curtains that didn't meet in the middle, (though this was mitigated by the fact the inner windows could be shuttered), wobbly toilet seat, plugs that were stuck in the hole, we couldn't work out how to manoeuvre onto the bidet to use it, so left well alone! The odd assortment of furniture (no two pieces matching or stable), the decor of the room, scuffed walls, chunks of plaster missing, everything you would expect from a squat rather than a hotel. All these could, it seems to me, be easily fixed with some inexpensive renovation work. But the worst of it for us was the smell of the room, both from the damp carpet by the bed, and the weird cleaner used in the bathroom that smelt worse than any public toilet. We could tell it was the cleaner as it was stronger after the room had been made up.
The location is great though with a short walk to the Spanish Steps through all the top designer shops, & a wide range of decent restaurants available.
Seriously though, if you intend to spend more than the bare essential number of hours (sleep time only), in your hotel accommodation, steer clear of the Marcus, as it will leave a bitter memory of a wonderful city.