My previous phone (before ICS on the galaxy nexus) was a nexus one with cynaogenmod.  Just upgraded to the samsung galaxy nexus and I will say that i'm very happy with the phone, but will echo everyone else's concern with the linked notification & ringer volume.  I also used to use the "silent hours" option in cyanogen to mute email & reminder notifications from 1am->7am, but left the sms notification & ringer enabled (i too, have on-call duty and need to get after-hours calls).   This ability to mute/change volumes for specific processes/services on a schedule was extremely useful, and I hope it comes back into ICS.