Xiomara's place was great! It was right in Central Havana near Vedado and not too far from Old Havana. We found a few places nearby where we liked to get coffee or fast food. It was also super close to a park that had a booth where we could get WiFi cards. Xiomara was readily available, friendly and helpful. Also, her neighbor Berta was very helpful and friendly as well. Your Spanish should be somewhat decent since Xiomara doesn't speak English. Berta does, which was great for certain questions we had, but we only saw her a few times.
The apartment is nice and private. There are plenty of fans as well as an AC in the bedroom. There's a TV in the living room and the fridge is stocked with water, beer and I think some soda too. It's kind of like a minibar so you'll be charged at the end for what you use from it. The bedroom closet also had a padlock on it which was nice for peace of mind.
There's a landline in the bedroom so you can make and receive calls in Cuba. Some nights were a bit noisey since it's a fairly active neighborhood but we never had trouble sleeping. We always felt very safe and comfortable there even walking around at night. Generally, people were just very friendly.
We stayed for a week and about halfway through Ximoara came by to freshen up the place as well as replace our sheets and towels, which was very appreciated. I'd definitely go back here.