They've held up surprisingly well. I've been very careful with them. For me, the newness hasn't even begun to wear off.
There are a few minor scratches, but those were caused by carelessness and are not noticeable unless you're down very close to the finish. I have placed very warm stuff on them with no problems, but haven't tested it with extremely hot items. I use hot pads instead. I'm also careful to use cutting boards and not cut directly on the surface.
I figure that after all my hard work getting this finish just right, I'd probably have a stroke if I damaged it. That being said, I also do not treat it like glass either. We put stuff on it, move it around and treat it like a regular counter. We just don't abuse it.
The product that we used is regularly used by restaurants on their tables. You can only imagine the abuse it takes in that kind of environment. I could probably be a lot rougher on the counters than I am and it would still do well.
On the whole, I'm extremely happy with how it has held up.
Hope that helps you! If you do this project, please post pics. I wanna see them!