Interesting set of results comparing the Panasonic Lumix GH1 with a G1 and a Canon 7D at:-
I did have a look at the DxO results & went back and looked at images from my GH1 & G1.
I did some serious pixel peeping and was hard pressed to spot any difference in resolution. There is some difference in terms of noise at higher ISO's with the GH1 being slightly better, but otherwise in terms of how the image looks on the screen I couldn't see any difference.
I then looked at some Canon 5D images and that was clear to see.
The GH1 is much "punchier" though obviously can't compete at higher ISO's.
Plus the 5D does have a much better Dynamic Range and deals with "difficult" exposures much better.
However this is at the expense of contrast and overall image "pop" which is the best way I know how to describe it.
Its one of the reasons I use a 5D MkII for indoor events etc, and G1/GH1/GF1 for landscape etc.
Some time ago an English photo mag, maintained that at low ISO settings the G1 outperformed both a D3 and D300 in terms of resolution. Having used both of those cameras I would agree with that.