Stayed with my wife and 2 year old son for four nights. The locality is fantastic, 10 minutes walk to Rambla Poble Nou with plenty of excellent food, drink, bakeries supermarkets etc. Also 10 minute walk to the beach which is beautiful. A bucket and spade was provided which is a lovely touch. 15 minute walk to the Zoo/Parc Citudella which is a great place to spend an afternoon. Metro is around 10 minutes away and easy to use. Buses seem to stop very close to the apartment but we never used them.
Jane's husband provided a transfer service from and to the airport which was great for us. Found the area very safe.
The apartment is small but has everything you need. Very clean and well maintained. There are a few stairs to climb but I found this fine with my son. The apartment is a traditional style with a terrace facing the road and wooden style shutters. As such the road noise is loud at night but it didn't bother me. If you are a soft sleeper you may need ear plugs. Kitchen is well equipped.
Hosts looked after us really well. We never had any issues with the flat but was reassuring that they lived five minutes away.
In summary a well equipped flat in a great part of town, close to many attractions with helpful hosts. Would not hesitate to stay here again.