We stayed at Walter's place in May 2014. It was a very good experience.

PROS:
Walter is very nice and helpful;
Location is superb - in the historical core and walking distance from the train station;
The apartment was clean, bedding was clean and abundant, olive oil, coffee and other kitchen staples we found in the cupboard were helpful and so was the bottle of red wine Walter treated us to!

CONS:
None really, the only thing you have to be mindful about is the toilet and the shower room are both really really small - but we liked the challenge! :)

Overall, we highly recommend Walter's place.