Still 2 years less, mind you! Unless they give you more for registering the card.
The longest I ever held on to a GPU was about 1.5 years and at that point the warranty becomes a selling point. Most people will prefer a GPU with a transferable warranty and in my experience it helps command a slightly better price second hand.
Now that on it's own would not be enough for me to spend the extra £40, but the ACX 2.0+ is a better GPU from the reviews I have read. It's quieter and has a better stock clocks.