The Merrill's on the other hand far exceed it in terms of resolution, even slightly besting my 24meg RX1, but only at base ISO of 100.
Really just totally different cameras as the GR is quick to focus, has nice battery life (shares same battery as the Sigma's in fact) and you can use it at higher ISO's, its very customizable, etc
DP's really aren't too fun as a general shooting camera. Awesome when you can compose a nice shot at ISO100, as the detail is unreal, but otherwise they aren't very fun to shoot.
I'd rather view them as a compliment for one another, and both are pretty great values (plus share a battery)
GR for snapshots, street stuff, night shots etc, DP for landscapes, working from a small tripod etc