I personally own Astro A40's and have done for about 2 years now.
Ok so my take on them: Amazing headset, very comfortable, great sound quality. I don't really have and complaints at all!
The cost: Ok so they ARE without a doubt, an expensive headset, but if you can justify using them on a regular basis, then the cost isn't the most important thing. When i bought my Astro's I was only working weekends and had 5 days a week free to play games, sad I know, but that's the situation I was in. On average each week I was probably spending about 5-10 hours per day on my Xbox playing COD and so the headset had ALOT of use. If I think of all the hours of use i've had from the headset compared to the total cost. I can 100% justify spending that kind of money.
Ultimately, if your going to spend money on A40's and then only use them for say 1hour per day, I can't see it really being worthwhile. However if your going to be consistently using them for long period of time, on a regular basis, then 100% spend the money and get a premium headset.
If you have to question the cost, then it probably isn't worthwhile for you. There are cheaper options available.
In short, in my own experience, Astro's are worth every penny.