What did you like about the PS3?
What would you like to have different?
Both the PS boards are a "hybrid rocker" a progressive 3 stage board
if you like(d) the PS3 maybe the new PS 4 will work well. there is a video that describes it here. http://liquidforce.com/boards_s4.htm
and you can watch the one for the PS3 too for comparison.
I have not ridden either but i have heard others say that the ps4 lands softer than the ps3 and... well, just wait for someone to comment more on that
As for slingshot, with the information i have, i would recommend the new slingshot reflex because it has a progressive 3 stage rocker as well and will perform somewhere between the recoil (3 stage) and response (continuous).
Send us some more info for what you are looking for... and of course there is the ever present cliche, "Demo, IF YOU CAN"