I've used it before, you can carve it, it is a bit springy and you'll find it can contain large air pockets so don't expect to achieve much more than a basic form. another thing to watch out for is when you're carving it you can come across pockets of uncured foam, these will expand out when exposed to air, its not a major issue though, you just wait till it cures and keep carving. Don't get it on your skin, its a right bast to get off. Personally I prefer carving dried floral foam, its much more rigid and better for building up shapes. I've sculpted quite a few vac forming bucks with floral foam covered in bondo, it works quite well.
