The stock system is way better than a standard one for sure, but it can be a real pain to get in the right position sometimes in order to have the right spacing. I.e. you have to be just far enough away that you can swing the arms out and telescope in/out enough to get the arm over the pin.
Mostly this is an issue on attachments that have a fixed pin that you have to go outside the end to make the connection. Ones that have a removable pin are much easier.
I was also looking forward to the feature of not needing the equipment to be level with the tractor - that can be a real pain sometimes.
Pat's may not be as big of an advantage as I thought it would be - many things sound better than they really are, but it gets lots of good reviews.