Wanted to be preemptive amid all the posts about the thumb stick wear on the DS4.
My order just arrived:
ORB Controller Thumb Grips 4-Pack
Fitted them and played AC4, NFS & Killzone.
They fit nicely and make the sticks a little larger and overall they feel great as I have large thumbs (found the normal sticks a little too small).
The come with convex grips (shown fitted) and concave which have more dimples on them.
The concave ones aren't very good and press in when you use them as the stick itself isn't rounded underneath.
I ordered 2 packs so I can have the convex ones on each of my DS4s.
Really happy with them for £3 a pop!