Great stay with a great host!
It is definitely noisy outside (even late into the night) but any lively part of Amsterdam is going to be a little noisy. You'll sleep well anyway on the amazing bed (memory foam) which is so above what we were used to on our travels.
The location is very convenient to downtown. We bought transit passes but ended up walking a lot more than we expected as the apartment is so close to the city center.
Highly recommended that you stay with Har!