A brake makes a nice addition.
I have used several joggers, some with a brake and some without. First off, the Chariot is the nicest I have used. The option to add all the accessories such as a brake is really nice. The brake was not too hard to install, but I did run into some confusion. The one point I will give is to remove the hand brake from the cable as it does not tell you to do this in the instructions and is necessary to thread the cable along side of the stroller upward support. It is not the best brake I have use and the adjustment sometimes does need to be checked, but it makes my chariot complete. A nice touch is you can lock the hand brake and/or the back wheels for immobilizing the carrier. One concern is the cable is directed underneath the double stroller and can dangle down. It has not caught on anything as I check it each time and I am developing a way to have it concealed. As for the fender/brake assembly I leave it up all the time even when pulling with a bicycle. It seems to help keep debris out of the carrier and off the children. I do not have the stroller kit and therefore no opinion in this regard. It helps with a functionality that I want and certainly helps make my jaunts with the kiddos more enjoyable. I would buy again.