I Have both the Bose and the Zulu headsets, so I can speak to this. I do notice the quirk on the Zulu's mentioned here, and I thought it strange at first, but then realized what was causing it, and it doesn't seem to bother me anymore, although I only have about 9 flights on them, after having used the Bose for 10 years. Here are some differences I've noticed:
The Zulus seem to fit around the ears better than the Bose. (Of course, I was told as a kid that I was born with full-size ears and grew into them. I still hate Disney for bringing out Dumbo when I was a kid!) So, I have noticed 2 things--- they seem more comfortable around the ears than the Bose, and on takeoff at full power, they remain quiet. The Bose will sometimes break the seal at full power and I get a lot of noise unless I remember to adjust them properly and make them tight, which of course I forget to do more often than not.
The Zulu's seem to have a more senistive mic, and pick up extra cabin noise, more so than the Bose. However, I did notice that the mic gain looks adjustable on the Zulu's and I will try to adjust it this week end.
The mic boom is a little shorter than the Bose and other headsets. It seems to sit off to the side of my lips rather than directly in front.
The "Front row center" button on the Zulu dramatically increases the music experience.
The bluetooth on the lightspeed is wonderful, especially for receiving a clearance while on the ground at a remote airport, and for calling Carol to open the hangar door when I taxi in.
Is there a major difference between the two of them? Can't tell yet. We traded one of the Lightspeed 30G's for the Zulu, which is a nice deal. Carol and I traded headsets on an Angel Flight this week end and when I asked her if we should trade the other Lightspeed in for a Zulu, she said let's wait and see.
I assure you that both of them are a great experience. The Zulu's are jsut newer generation with some nice features.
Vic