Chalk or wallpaper - Which version do you prefer?

The chalkboard version or the wallpaper version?
Since seeing these gorgeous grey bedrooms, I'm tempted to vote for the chalkboard version. I love how the range of grey hues (the cupboard, the chair, the concrete floor) on this image come together...I also think, given my recent posts, that I'm going through a gray phase...
However, the practical side of me thinks that it may be quite messy to do at home compared to the wallpaper version by Lisa Bengtsson which makes a great feature wall and is slightly more flexible. What do you think?