Well I've never heard the AZ's but I have Nordost Frey Ic and Sc. To me at first they sounded thin but later realized what I was hearing was more 'air' between the instruments and vocals. The difference between the Heimdall and Frey is ever so slight.
That being said I am currently demoing the new series 2 (my dealer kept the Heimdall's). They are quite different. More low end and much more liquid sounding. Naturally the Tyr2 does sound the best but at it's price point the Frey2 is very close. $8800 vs $3800 for 4m Sc's. Also the series 2 Sc's are NOT available in bi-wire. As far as the Ic I again prefer the Tyr2 and it's price point isn't as dramatic $1400 vs $2400 for 1 meter.
That being said I am currently demoing the new series 2 (my dealer kept the Heimdall's). They are quite different. More low end and much more liquid sounding. Naturally the Tyr2 does sound the best but at it's price point the Frey2 is very close. $8800 vs $3800 for 4m Sc's. Also the series 2 Sc's are NOT available in bi-wire. As far as the Ic I again prefer the Tyr2 and it's price point isn't as dramatic $1400 vs $2400 for 1 meter.