The splines are a bit of a weird one as the drive faces are effectively static in relation to each other in transmitting the torque so don't really have much lubrication required as such. But the sliding to accommodate suspension travel does but it's not too demanding.
Most of that type seem to use straight lithium grease. It's more important that it's actually in there than the type of grease really, so there doesn't seem to be any reason to switch to something else. Making sure it's greased to schedule should be sufficient.
If you had to consider something else it would be CV grease as it has a very high resistance to spalling in high torque applications.