I thought Forge of Darkness was pretty good. Lots of really good stuff with the Tiste, and the other race of people I won't go into detail about, amnong other things. I doubt most folks have read the book and I don't want to spoil anything, but it fleshes out a lot about the elder races and gods, while also opening the door on a lot more questions. Fall of Light, on the other hand, was not so great. I can deal with the philosophizing that Erikson likes so much but Fall of Light was just totally over the top with it. I may need to revisit that one but I recall being extremely disappointed when I finished it.
That said, is there more art than what's shown there for Forge of Darkness? Surely there is. I might need to get in on this when they open it up to the public. I've regretted not buying the special editions that have been posted in the past.