I spoke with a number of outfits at DSC last year who had made a habit of exhibiting at both SCI and DSC for years.
They do not plan to attend SCI any longer...only DSC. Reasons given were volume of traffic/sales, and treatment from the organizers.
Specifically, I heard that the exhibitors at SCI were being bled like a cash cow, whereas at DSC they are made to feel like a valued partner.
It appears to me that without some major turnaround, the SCI conference is going to die.
Unless the timing or travel prohibits, DSC all the way.