Yeah, my screen off sound seems to lag as well, but I got used to that.
One thing I noticed about these third party phone vendors is that, they may be scamming you. When I got my Nexus at Best Buy, it came out of the box with 4.0.2. All the phones are supposed to come out of the box with 4.0.1, according to a Verizon employee I talked to. So it is possible that these phones with hardware related reception issues could actually be CLNR phones, without our knowledge. Keep aware of that, make sure you are prompted to update to 4.0.2 out of box, otherwise return it because it is NOT a new phone.