I got a couple of Bad Squiddo Amazons finished up this weekend. I experimented with a new contrast technique - I did an Agrax Earthshade wash over a grey undercoat, then a heavy drybrush of Tyrant Skull before painting them with Contrast.
I think they've come out a bit dark, which is fine for a lot of the models I paint, but I do want to do some experiments with brighter, more vibrant colours. I'll need to do some experimentation to work out how best to do that in the future.
I also discovered that using technical stuff like the Games Workshop verdigris effect can go wrong with Contrast. My usual plan of wiping off the excess ended up wiping off some of the finished Contrast, even though it was dry. It's really not very robust at all! I fixed it, but always varnish any models you've painted with Contrast.