I've had it since the closed beta came out in June or whenever, then pre-ordered because of discount, they haven't updated too much since then. There's more stuff to upgrade on your towers, and the levels can change shape, and you can add/move platforms. None of the various commander powers are in or anything.
They just added in controller support last week. Workshop is up but you can't download anyones maps yet.
It seems slightly easier than the original, but I guess the two maps in the original's demo were pretty easy too.