I've seen many reviews on gaming headsets mentioning that the bass is not good. You'll find this is a "problem" with most of them.
Headsets are designed to have a lower base so other more important sounds can be heard over explosions. For example foot steps, bullets going by, and the sound of your enemy reloading.
If you want good bass reproduction buy a pair of headphones for music, if you want a heads up in an FPS game get a gaming headset.
This headset is good for gaming, but it is also important to have a decent source. Without that you might as well buy a cheap set of cans.
Personally I am now planning on getting a 5.1 head set. Originally I thought this was a gimmick, but after seeing for my self they really do work! Games which have been enable like Battlefield 2 you can hear more and the direction the sound is coming from. The Roccat Kave are awesome for this.
I hope this helps you make the right decision when splashing out on a headset.