I took another look at that painting I wasn't happy with, bearing in mind crit from friends on and off line and my own feelings about what was wrong. I spent about 10 minutes on it with oil paint scumbled over in areas, allowing the acrylic underpainting to shine through and leaving a lot untouched.
The oil paint instantly improved it (for me anyway!) - the vivid blues are toned down but still glow through and now have recession. I heightened the ochre tones that you get in the grass on cliff tops, which plays nicedly against the blue. The more vivid grass and subtler sea/sky now balance much better to me and I prefer the scumbling and variation in colour that I can get with oils. I also lightened the light areas of the cliffs a little more and added more ochre where it showed on cliffs and rocks in light scumbles. The sky is more interesting and melts into the sea without a clear division along the full length.
Below you can see close ups of the layers and scratches and scumbles - which are easy to achieve with oils or oils over acrylics - but I just don't seem to be able to get this with acrylics alone :>( . Acrylics aren't opaque enough to cover totally like oils, one major problem to me, nor translucent enough for me to swish a thin thin layer quickly and freely without hard edges (it takes work to soften the edges enough and the freedom of the mark gets lost). My natural method of painting is subtractive as well as additive and oils just work so much better for me.
I think I have to accept that for me acrylics work beautifully in mixed media but not alone. Maybe for a painter who puts colours down and leaves them alone they are perfect - or who builds subtle layers in an abstract way without marks like Tina, where they are perfect - but not for me who loves marks in my own work - some subtle glazes, some scratching through, opaque areas, translucent areas and layers.
Details: (the paint is still wet so is a little reflective)
previous version that I didn't like:
What do you think? better?