Yea for the Logitech I'm not sure how much the improved Mic would help.
For the Corsair, its not so good that you can hear a pin drop. I've only used the mic a few times and those times people heard me fine without problem. My brother pretty much wears the thing all day every day now and he chats with people on skype, while playing games with it on or he plays games with online chatting systems and uses it to chat constantly. I've asked him before when I was writing a review for it I asked him and he said everyone hears him really well and easily, but didn't give me more details.
Long story short, I think the Logitech probably picks up your voice when speaking a lot quieter but the Corsair hears you when speaking in a normal volume...