I have a DP1 merrill and the image quality is fantastic out of it, it renders micro contrast and colour unlike any other digital camera out there. Better micro contrast seems to be what gives it a more 3d feel, bayer sensor cameras tend to look flatish because of the bayer filter.
Like other people have said it's not too far off a d800 d800e for perceived resolution, which means if you wanted you could print very large.
I didn't get it for the resolution but rather the lack of a bayer and AA filter which is what gives your files a different look, in some ways more like medium format film, though still can't quite get that Velvia 50 6x6 colour or feeling of depth!
It does have some significant drawbacks compared to a modern digital camera. The battery life is terrible the two batteries get me about 70 100 shots, though I don't mind means I take less photos and saves me time processing them in photoshop
other thing is the file sizes are huge 40 to 50mb Raw files and you can get 80mb tiffs from the raw, if you use it a lot watch your hard disc space evaporate.
The write times are insane 15 seconds to write a RAW, though you can shoot about 7 in a row before buffer fills up, but you get no preview until they are written to card. I started shooting film again so appreciate that I can see the picture after 15 seconds and not two weeks!
There isn't a camera in the price range that delivers anything close to the image quality, if you can live with the drawbacks (having shot film again they don't really seem like drawbacks anymore) it's a superb camera.