I stayed at Viola's place for over 2 months. It was an amazing experience and I definitely recommend it to anyone who is visiting Valencia. The apartment is very spacious, clean, comfortable and well located. Everything is as described. There is a tram station and several bus stops close by although you can easily walk to most of the main attractions. For example, the city center is only a 15 min walk away and the beautiful Turia Garden is within 5 mins. (From the Garden you go to almost anywhere in the city)
I work online and I found the WiFi to be fast and reliable, which was a definite plus!
Communication with Viola was pretty good.