I'm a fine art photographer who works in both color and B&W. I have a 3880 devoted to color, and a 3800 devoted to piezography ("Cone inks".) IMHO, the difference is stunning. First, a gray-scale ramp chart will print all the way from 0 to 255 with piezo inks, whereas with ABW the best I can get is about 11 - 254. If I seriously tweak the image in the shadows, I can get to about 4 or 5 with ABW. So if you want shadow detail in your prints, the choice is obvious.
Second, the 7 shades of ink allow for a much more realistic presentation. This is difficult to describe, but I usually say (and some perceptual collectors also note) that the whole image looks like you can reach into it (where as a "normal" B&W looks like... well... er... a photo.) In fact, after 50+ years of looking at B&W photos, this takes some adjustment to realize how much better it is.
If you've ever seen Edward Weston's Pepper #30 as his own actual print, you'll have a sense of what I'm talking about.
All that said, there is not only a "viewing curve" but a learning curve in Photoshop as well. The distinction is that now you're dealing with a full range of tones instead of just setting the black and white points, and letting the rest fall. At first, you'll think the images are too "flat" but that's not the fault of the inks... that's the amount of learning you need to do to get the kind of print this stuff produces.
I've had a number of photographers come up to me at shows and express their delight that I'm continuing the tradition of selenium printing... only to be stunned to discover it's a piezography / inkjet print.
I've been doing this for about a year or so now. At first I cringed at the mess of refillable carts; and the expense (although cheaper in the long run). Clearing out the old color inks was "non-trivial" and time-consuming. And I've come to develop my own curves to apply to the final image to make the print "just-so."
But for me, and in my business of selling my own photos, I would never trade back to ABW. I'm a very happy piezography user... and my prints sell. :-)
hth
Tracy Valleau
aperturef8.com