No, this isn't an upgrade to the Samsung Galaxy S II (that would be the Samsung Galaxy S III). It's an upgrade to the original Samsung Galaxy S. Yes, you thought that was the Galaxy S II. So did we. It sits in the wide gap between the Galaxy R and Galaxy Y, so it should be a Galaxy M or Galaxy W. But it isn't.
We think that Samsung may have painted themselves into a corner with their naming convention, and have managed to cause some market confusion.. which is a shame because the Galaxy S Advance is a very decent looking upper midrange smartphone which is exactly the sort of thing many customers are looking for.