Yes, plenty of ponies in both. At Hollands Wood we've had a pony stroll into our camp area, pick up a tupperware box, get the lid off and start eating the salad!!
I think in a way I prefer Hollands Wood. I went to the rally field at Roundhill and that was great, but on the main part at Roundhill it was a bit flat and open. What I didn't like about Hollands Wood was that it was so under the trees that it shielded us from the sun too much and there wasn't much grass underfoot, it was mostly ..... what's the word ... fallen leaves (that not the word I was looking for, I'm sure there's one - mulch maybe).
But in Hollands Wood there's lots of little areas to make your camp in so it feels like your own space. Roundhill is more open.