It's not much
Although the "default" is to get mad at Microsoft for locking down exclusives, Sony has one in the pocket for Destiny. It involves a small amount of content, but content nonetheless, and you can get a full look of what to expect in this new video.
Basically, it includes the PVP map Exodus Blue, the Strike map Dust Palace, and a few exclusive weapons and outfits. It wouldn't bother me that much if I didn't play it on a PlayStation console, but I'm sure there are some hardcore players out there who want to know the time limit of the exclusivity -- if there is one.