After John did his test with the new washes on his Death wing Army, I had to try it on my Orks. I decided to do a painting test in which I tried to weigh quality vs speed. Below are my results. I painted for about 45 minutes.
I started out with two guys, one got the Dark Angels Green, the other the Knarloc Foundation paint.
After that dried, I dry brushed the one guy, let's call him Dark Angel, with the usual Goblin Green. I tried on purpose not be too precise. It's hard for me and all my Orks I usually try to paint perfectly, but this was a test.
The other guy, Knarloc, got a wash of the new Badab Citadel Wash.
My first impression was that the stuff is much lighter then inks and you need to keep throwing it on to really make shadows dark. I can totally see that on a white primered model it works great. Eventually I added some black ink to dark everything up.
In the meantime I gave Dark Angel a dry brush of SnotGreen and started working on his gear. I painted his outfit black, put Tinbitz/Boltgun Metal/Mithril Silver on his equipment and painted his teeth with Bestial Brown/Bleached Bone/Skull White.
After all that, Knarloc was still not dry, in the mouth especially. The arms looked nice and subtle and the picture shows the washes work really well in muted fashion.
I gave Dark Angel a quick coat of glossy varnish over his outfit and there! He was finished. Poor old Knarloc, he still wasn't dry and I could not even put a drybrush over his face without smearing.
Conclusion, for speedy Ork Painting, stick with the drybrush method. It saves you time and will make your model look really punchy. The washes will work well on vehicles (subtle rusty look) or white models like the Deathwing or Woodelves in winter outfit (one of my armies) and they don't seem to be so intense as the inks. I LOVE the fact that the washes are MATTE, that's awesome.
I am not convinced yet but will try more things and keep you posted.