[Elecraft] Better receiver: KX1 or Sierra?

[dmaliniak at penton.com]

On the Wilderness Radio website, QRPBob quotes a Sierra receive 
sensitivity spec of "better than 0.5uV for 10dB S+N/N selectivity."

On Elecraft's website, I can't find any comparable specification for the 
KX1.

I guess what I'm asking is: Which rig has the better receiver? Any 
opinions from QRPers who own both? While we're at it, how about the K1? 
Where does that fall in the mix receive-wise?

Thanks in advance for any input.

72,
David, AD2A
Glen Rock, NJ