Rubber ones on the P07. Sand ones on the P09.
I think I like the sand ones better. As stated in an earlier post, much "grippier."
I've seen some people post that they felt the factory grip surfaces on the P07 were "too rough."
But, as you mentioned, I had a day at the range when I was on the verge of melting and I was sweating to the point where every 2 or 3 rounds I had to re-grip the pistol to get it right in my hand again. I came home, ordered the grip panels and installed them when they came in. I went with the sand on the P09 so I could try something different, see which one worked best and "consolidate" as needed. So far, I haven't had a repeat of the issue so I've not changed anything.
We also put them on the XD's in .45 acp as they tend to move more than even the .40 S&W P07.