Denon budget cartridge compared to $700 cartridge

Witha set up like that you should go towards the Lyra Helikon or Shelter 901 cartridges............

try the dynavector karat...i run that on my scoutmaster with jmw 9 signature arm and a lehmann cube se. in my opinion its a very good cartridge and one that mates well with the arm. output is a little low for the cube, but its a real nice combo.

Based on your system and your cartridge budget, I would recommend the Dynavector 17-D Karat or the Shelter 501 over the Blackbird. If you do that, you should also consider getting a new phono preamp. I am former owner of the Black Cube SE, and have real respect for it, but I don't think it is ideally suited for use with lower output MC cartridges.