For sure you lose resolution. I don't know what happens with the Sli3r's. I know Slic3r moves the Z-Axis in partial steps when it is doing support material. But Marlin will work.
I think you are worrying too much about partial steps. Everybody uses the micro-stepping and it seems to work OK.
I think you are worrying too much about partial steps. Everybody uses the micro-stepping and it seems to work OK.