The Eton College description is pretty much spot on. I would call it a rather intense blast of citrus with a bit of wood. Haven't found anything else quite like it. It can be very strong, so if you get it, I would suggest that you go pretty light, (one spritz or only a few drops, depending on how you apply your cologne) since it can be very intense and overpowering if you use too much.
However, since I have found nothing like it, I almost always get some kind of reaction or comment (positive) when I wear it.
It's not that easy being green...