Bold part implies that you are talking about overall Sand manipulation....
In which case...Gaara>>>Crocodile
Can Crocodile even manipulate pre-exising Sand? What about Sand that he generated, after it has detached from his body?
1-He has a passive Logia body defense
2-Moisture absorption...but can get wreck by a little moisture
3- A few cutting attacks.
4-Generate Sandstorms
Gaara
1-can control pre-existing Sand.
2- He can create more sand from the ground.
3- He can use sand as an extra sense.
4- Can fly
5- Use cutting, Piercing, binding, and crushing attacks
6- Form a giant Avatar and other constructs (has helped stop a meteor)
7- Seal opponents
8- Control the density of his sand.
9- Passive defense that can usually keep him from taking damage