My husband and I both got the Nexus S last summer.
The deciding factor for me was the Sprint employee who assured me that as a pure Google phone, it would be the first phone to receive the new version of Android when it came out.
We are both extremely disappointed with how this update has been handled. Sprint and Google have both been silent. I won't be buying another Google phone.
Sprint, this isn't fair. You owe us answers.
Here are the official binaries everyone has been waiting for. http://code.google.com/android/nexus/drivers.html#crespo4giml74k. Now when these will actually be pushed over the air by Sprint, I have no idea.
If you have the skills and fortitude to do the update yourself, looks like you can. If someone is sucessfull with updating using the 4.0.4 driver, please post back to this forum with some hints on how to do it.