What a not so noticeable in the older controllers is the wear of the analog sticks. This is of course again very nice with the new and you will slide off easily even less than they already, since these small nubs are there.
The battery compartment is located perfectly on the controller. When my older controller that is something shaky and sometimes the contact goes away off the Xbox. But what may likely be because these are just a little older and abgenutzer.
To form you have to say which is hardly yet. Although there is only my personal opinion, but I think the controller is just perfect in the hand.
The only drawback, is in the black controllers compared to the white that you can pretty much see the dust on it. Locate the black but still chic and blow over it again with the dust is gone.