Walking with a split-board on hard snow (glaciated and steep) is worse than skis, but I dont like to use skis either then.. Otherwise the split-boards are excellent! I only have a few issues with them:
1: They are to wide to follow in the tracks made by regular skis.
2: They are very expensive.
3: They are an uncommons sight, so everybody wonders what you are walking on, before you assemble it on the top.
4: Snowboarding un an glaciated slope is harder with a board than on skis. (might be my lack of skill )
5: You better be able to go downhill all the way to the car, or you have to de-assemble the board again (no problem where I live)

But all the positives outweight all this..