My wife & I both bought new 8330's last night. It seems like on every other call we can not hear the person calling us even though they can hear us.
- Phone rings, I hit the green 'answer' button and its 50/50 whether I will hear the caller.

Any ideas??

Please help!

That sounds like a network problem. Sprint my have a bad Voice channel on there switch or who ever back hauls there traffic. I would make some test calls to each other and to landlines and other things to see if there is something in common.