AFAIK Screen makes only CMYK inkjet digital presses. While I can imagine that inkjet process can give better results than HP Indigo's Electroink (e.g. the above mentioned DreamLabo really kicked ass), I doubt it will give optimal results in case of B&W images. Another limitation is the small variety of papers, and the unpleasant stickiness of inkjet coated media (another drawbacks of DreamLabo).
Indigo can print on virtually anything using up to 7 channels - my friend works in R&D on Indigo screening and separations improvement, and the results he showed me were interesting. There's also significant quality difference between Indigo 5000 series and 7000/10000 series.
I didn't say Indigo is not good at all, it is a really good digital press, but with certian limitation.
1. I have talked to a lot of on site indigo operator, 80% of them said the system is a bit hard to work with by some how. (I haven't spent too much time on indigo, at least not like them as a day by day operator, so I can't really comment on that)
2. You said it can print on virtually anything, yes, virtually. Indigo does require special coating on paper to get optimal result. When it prints on uncoated paper, it can go really bad.
3. 7 channels is great, specially they can mix a lot of special color in it. But not the clear and the white ink. None of the digital press can do good white ink and clear ink, besides MGI, which is specialized for Spot UV ONLY. And for white ink, just go with either silk screen or UV-curing, they are they best solution.
I would like to see if anyone has a DreamLabo in Asia, as long as I know, Canon had demo once in Australia, but not even in China.
To me, on-demand book print is very mature already. No offensive, but in Lula, I think most of my friend here are very picky, too picky compare to the mass market. An indigo 7/10000 cost more than a M-Benz S class with all 7 channels and other module, how many book needs to be printed to gain the investment back, that's a tough question to ask.
So you are right, the best way to print a very decent book is to print it by ourselves and either learn how to bind it or send it out for someone who is profession in it. Otherwise, Blurb, Adorama, Bayphoto or Artisan should be good enough for everyday picture.
aaron