We loved our stay at Lucas apartment, it was ideally situated for nightlife, restaurants and was easily walkable to the major sights. Emiliano was so helpful for the check in and anything else we needed- the video showing both the front door and apartment door was super useful!
The bed was extremely firm which was OK for us but might not be for some. Only issue we had was there was only one pillow provided and it was quite flat, otherwise a very comfortable apartment.
Beware for noise from revellers coming back from the nearby bars, especially if the football has been on! I had ear plugs so was ok, although you're far enough away to not be bothered by noise from the square.