Take the CJV150 and add a second print head. Now you have a CJV300. The quality will be the same and the speeds will be as fast or faster depending on the ink setup. To take advantage of the fastest speed you want to set it up with CMYKx2.
I have never been a fan of adding colors other than CMYK as the difference in quality is indistinguishable to me and it costs you a significant amount of speed. I just printed some black and white prints on the CJV150 perfectly without the light black the other day. No magenta or cyan haze at all. Obviously other people would disagree but that's just my 2 cents.