Looking at the missing features in the Quartz release, I'm wondering if you have a roadmap for this version you can share. We just completed migrating from the old Runtime for WPF before you released 100.1, and haven't looked too much into the quartz release.
We currently rely on GroupLayers for our show/hide functionality, though I expect we can circumvent that limitation on our own.
The other part I'm wondering about in Choosing the right version | ArcGIS for Developers is Geographic Transformations; what do you mean by this? I see GeometryEngine.Project is available, but was wondering if you are referring to supporting multiple Spatial Reference in one map, automatic projection of graphics, or something else entirely.