Very good! The apartment is big, comfortable and we found it perfectly clean.
The position is very good as well as you can reach the Stare Mesto and Mala Strana walking in less than 15 minutes.
Having two showers and two toilets was perfect for us, being 4 people. The kitchen is beautiful and fully equipped.
We did not have the chance to meet the hosts in person but they have been very nice and helpful by e-mail and always answering within few minutes.
I'll definitely choose it again if back in Prague.