The set is very good and the train really looks great when it's actually built. It took me about 3 hours to complete. The pairing with the remote control was not an issue, after following the tutorial video. You only need to do it once, then the remote and the receiver will recognize themselves every time you turn them on.
I also believe that this particular train really needs an extra tail cart to look symmetrical and I'd like to share my experience with adding it, without purchasing a second set.
I contacted the Lego Customers Service at the beginning of August, shortly after the set was released. I was pleased to receive immediately a list of parts but, unfortunately, they were not what I was looking for.
Maybe it was too early in the process, but the Customer Service was not able to provide a list of the all the actual parts to build the cart as you see it in my picture.
I ended up compiling the list by myself, based on the parts needed to build the engine and modifying the wheels assembly in order to remove the motor. It took a while on the phone to go through all the parts and the required quantities, but luckily that process was not too bad as all the personnel at Lego Customers Service I dealt with was really helpful and, after the issue with the initial list, made sure I got taken care and received what I needed.
Some parts are really new and it took about 10 days to get them all from the factory in Denmark, but I'm very happy with the final result. Cart could be further modified to add more windows and seat, as you have plenty of room inside without the battery pack / receiver, but I chose to have it looking like the engine cart.
I would recommend the Lego Engineers to come up with an actual list of parts to be purchased or, even better, to have a set with end cart directly available for sale, as it takes quite a bit to come up with the list and it's easy to make mistakes or forget some pieces.
Sorry for the long post, hopefully it will be helpful to those who wish to add the cart.