Exact the same impression I got while watching him. From economical point of view it's a great deal; Guarin is younger, better resale value and we'll get that 5th midfielder we've been looking for since summer. But seeing Vucinic in Inter's shirt will be difficult to bear.
It doesn't matter much where he's going. I don't see the point in this transfer if it involves Guarin. Sell him if you want, or exchange him with an equally good player, but not with someone who isn't half the player Mirko is.