This is a great spot if you want to weight lift with your host. Kidding aside, this was actually a pretty bad experience. A friend and I stayed two nights here. While their house/casa is quite nice and clean in a central/convenient area, Ariel and Elena were incredibly unwelcoming, seemingly unwilling to offer any advice, guidance, or tips, and the other amenities one should expect from a good Casa Particulares (i.e. nice breakfast) were virtually non-existent.
When we arrived, Ariel didn't bother saying hello (or making eye contact), but rather just asked for our itinerary and then grunted something unintelligible. I also tried to say hello to Elena (I think it was her, but since no one introduced themselves, unclear), but she was just as cold.
Our room was on a major street in central Havana (Neptuno) and, if you've never been to Havana, should know this is not actually a good thing. It's incredibly loud and smoggy. While clean with high ceilings, a (shared) balcony, and a nice bathroom, the first morning we didn't have any hot water in the shower, and the second morning we had a dribble of water in the shower (though a little warmer).
Our breakfast included coffee and guava juice (staple), fruit, white bread and butter, and two eggs. Our breakfast the second morning included the staples, yesterday's fruit stirred up in a cocktail, two eggs and a piece of lunch meat ham.
I've traveled a few times to places that are as underdeveloped as Havana, and stayed in pretty modest places. What often makes these an okay/acceptable choice is that the people who run them are actually nice, decent people that will try and make your stay a good, welcoming experience. This was not that. Ariel and Elena are not good hosts, at all. It was a bad experience and your hosts effectively consist of awkward young women scurrying about Ariel and meekly going into his room to ask him something about your stay, and then communicating this back to us, as if he couldn't be bothered with us. Look elsewhere, folks.