My kid plays on as many turf fields as grass ones in the summer. They don't allow metal spikes on any of them. Some have dirt mounds, some don't. I would have been in the grass and dirt category a few years ago, but after seeing how it plays and talking to the kids that play on it, I think it's the only way to go for college baseball if you want to get games in. There are different types of course and the technology is always changing, but what I've noticed is 'worn' turf has more of the black pellets showing than a sheen. The stuff is made of plastic. It's got a shine to it.