I believe I should preface my thoughts by saying that my first digital art program (back in 1998) was Fractal Painter 5.... which has since changed hands a time or two, and today goes by the name of Corel Painter 11. It was my first love of art programs, but over the years we drifted apart: it became more and more convoluted or perhaps I just discovered the clean simplicity that is Photoshop.
At any rate, for YEARS I have longed for a way to do wet-media (read: wet paint) simulation in Photohop, every time I've tried going back to painter I've quickly gotten a headache and ArtRage just can't cut it with large files or keeping layer effects intact (a must for the large complex paintings I do for clients).
I had all but given up.... but here we are, a decade after I got my little hands on Photoshop 4 and they are here! I can only related what an afternoon of "playing around" has shown me. And they work nicely. The options for the wet brushes have been expanded we now get to adjust things like: wet, flow, load, etc.... there is brush length, stiffness, angle, etc. In short everything you need to paint with that nice "squishy" wet paint in Photoshop.
I feel like I have much more to experiment with in this realm. I'm excited. =)
You can read a bit more in-depth review of the brush feature here: http://www.photoshopcafe.com/cs5/Wacom.htm
A speed painting using some of the new brushes:
