I like both, really. I liked the region when it was called Isshu, and I got pretty used to it until the region's name was localized as Unova in other regions, and I didn't like it at first, but I eventually got used to it, and I like it now, much like the other people in this thread. If I had to choose, though, I'd choose Isshu just for nostalgia like Nica, lol.