There were pros and cons to our stay with Marcos & Sergio.
Let's start with the pros! The location is amazing. It is close to all the lovely bars, restaurants and coffeehouses. The area Ruzafa is amazing! People are friendly, it feels safe and welcoming, we absolutely loved it there. You are close to the old center and LA Carmen, another great area, is not too far either. You can rent bikes just around the corner too!
Cons: we stayed for quite a while (8 days) and obviously knew what we paid. It is not cheap, but that was our choice. We would of appreciated a warmer welkom. There was no welcome book, the wifi password didn't work at first, the bed was broken on one side, there was no shampoo (it said there was) no coffee (2 cups would have been nice after a long day of traveling), 2 towels (a big one and smaller one) for 8 days and not enough toilet paper to last 8 days. There is a washing machine, but again, for the amount we paid, we would have appreciated these little things to be in place. We don't know Spain, were do you leave the trash for example? A guide would have been nice. We asked the hosts to maybe inform the upstairs neighbour(s) as their washing machine seems to wobble a lot and it woke us up 2 times during our stay. We didn't get a response (confirmation) from the host as I did inform him.
We would come back to this appartement, as it is spacious and nicely decorated, but for the amount we paid, we might try another place first :)