I own both headsets and have done for nearly a year now. I did review my experiences of both side-by-side but cannot remember where I put the review.
For me, they both have their pluses and minuses and it was pretty hard for me to say one was better than the other. I had the Bose bought for me as a present from my wife and the Zulu 2 I was given when a family member had to give up flying due to ill health.
If I was buying just one headset now then for me, it would have to be the Zulu 2. Since I did that review I have had issues with the Bose where it kept switching off during flight for no explainable reason. This was sent back under warranty and since it was returned have not had a further problem.
But I would still go for the Zulu 2 on cost alone. Not because I want to buy cheap but because for the price difference between the 2 there is absolutely no way I can justify the difference in quality with the price difference. The Zulu 2 for me is in every way as good as the Bose in both what it does and the build quality but for a much cheaper price.
Other smaller things that matter to me as well are simple things like the quality of the case supplied. The Zulu 2 comes in a hard case that is very protective if something is stood or dropped on it whereas the Bose is a soft case that would not protect the headset in anyway should the same happen.
Over all, with price taken into the equation, I think the Zulu 2 is a much better deal. With regards to battery life, I would say that the Zulu 2 has slightly better battery life but there really is not much in it.
The only way to really know is to try both as different people have different preferences.