Ava's place was very clean and well presented. The space is quite small and the bathroom could be difficult for a tall person to use (over 6ft) but otherwise a great place.
The place is close to the BART but as a few people have mentioned, it's an uphill walk (like most of San Fran) so I wouldn't recommend using the BART if you're carrying a lot of luggage. Otherwise for every day use it's perfect.
I didn't met Ava or Nico, but Nico was very responsive to our text message questions and was very helpful, he provided a lot of great suggestion for things to do and places to eat around San fran.
A tip for San fran: we really enjoyed using the new share-scooter system - Bird, (there is also another company called Lime). You just need to download the app and then can pick up a Bird off the street and have a great time zooming around the city (we mainly used it around Fisherman's wharf where it's flat as the Bird struggles uphill)