I haven't had the chance to listen to the new Leif series but I did have a demo case from Nordost that had the Blue haven through the Frey. I personally found the BH and RD to be a bit tipped in the highs and slightly weak in the lows. The Heimdall and Frey were better balanced. I bought the Frey's. I am currently demoing the newest Series2 Norse cables. They are very different than the original Norse. More liquid sounding with a lot more low end. So I would 'assume' the Leif series would be better than the BH or RD.
Never heard the AZ's
Never heard the AZ's