My girlfriend and I stayed at Alberto's place and we both absolutely loved it. Alberto's mum, Maria welcomed us to the house and provided useful and quick responses to any questions we had. El Cabanyal was such a nice place to stay, it had a great sleepy local quietness to it, without feeling detached from Valencia, which was a short journey on the tram or the metro (we liked getting the metro - about 10 minutes to the centre - as it meant we had a nice 15-20ish minute walk through El Cabanyal and through the amazing local food market). There's a great balcony and even with the low winter sun, we'd have warm uninterrupted sunshine for most of the afternoon - i'm sure it'd be even longer on the roof terrace too.
The house was spotless, everything worked, felt clean and well looked after. Maria was quick to reply and also flexible with our arrival and departure times.
If you're thinking of coming to Valencia and considering El Cabanyal, I couldn't recommend it enough. The whole area feels unique. It was so nice to go to the market in the morning and buy fresh food, make a lunch on the balcony and sit in the warm sunshine - exactly what I needed coming from London in January.