The SDC has 4 user definable maps/tables, the DCCD Pro performs calculations on the fly to determine diff lock, it doesn't have maps so I'm not sure what you mean by they are adding this feature. It's up to you to determine which you think is a better means of controlling the diff, both have their upsides and downsides.

The maps in the SDC can be set by means of throttle position or map vs. ground speed. This then gives the diff a % lock based upon the value in the table (or map). Added to this value is a calculated value in order to try and maintain the desired slip (the desired slip can be set based on ground speed). I would suspect that the main tables should really all read 0 and the desired slip should also be 0, as unless you are drifting you don't want the rear wheels spinning. It's worthwhile pointing out that the SDC switches between maps based on the position of the thumb wheel only.

I actually believe that the factory computer could offer the best "auto" solution as it has the ability to change the diff lock based on roll (G sensor), steering angle (sharp steering angles should have less lock), wheel speeds (hence slip) and yaw. The only downside to the factory auto mode is that its sensitivity can not be tailored to the specific driver (i.e. there are no adjustments).

You can be sure that out of all three possibilities (motec/dccdpro/OEM) that the OEM system has had by far the most time, effort, money and brain power put into it, though obviously bear in mind it has been developed for a road car...

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