Bought a used 848 a few months ago that came with Zero Gravity seat. It's comfy and I can only compare it to the DP Superpole seat; I've never sat on a stock seat. Both the DP and ZG seat are nice in their own regard. The ZG feels more comfy for longer street rides, yet still provides a low profile for aggressive track days. The DP is a hard plank that's surprisingly comfortable (slightly less than the ZG), but really shines on the track when getting off the bike. The sides are super tacky and you get very good grip and feel of the bike between your legs.
I'd say the ZG is the best "all-purpose" seat, whereas, the DP is a purpose-built racer seat.
Good luck and I hope you get your seat soon.