I highly recommend Vincent's place. Great spot, 5 min walk to the Old Town square, less than 10 min to the Charles Bridge.
We didn't get a chance to meet Vincent in person, but his assistant Viola was there to help us with everything. Apart from that Vincent quickly responded to all of my questions, providing useful tips and information.
Room was just as described and shown on the pictures - very clean, neat, spacious, perfect for 3 people. Rest of the apartment was nice as well. Bathroom was clean, kitchen supplied with all necessary stuff like cups, plates, cutlery or pans for cooking.
Basically you get everything you need for your stay. I will stay with them again if I come back to Prague!