Overall had a great stay. Karen is easy to communicate with and very responsive. The apartment itself was nice and matched the description. Location is excellent -- walking distance from a lot of great spots in Roma Norte.
The only issue we had was that there's a lot of noise from outside that can be heard in the apartment. However, this is not the fault of the apartment / host, rather just a factor of being in a popular neighborhood.
In general, I would recommend this airbnb.