I recently stayed at Hotel Jazz for 4 nights in early July and could not fault anything.
It was very convenient to get to on the Aerobus, the staff were very helpful and friendly and spoke very good English. The hotel was modern and clean with a very minimalist decor. It was very central to everything and La Rambla was a pleasant distance on foot.
If I return to Barcelona I would definitely stay at Hotel Jazz again.
Experience posted by Jayne, August 2012.