"We have gone for the 9V system, to the power functions system, with a side detour to the mindstorm systems, and now to the power-up system. And largely, these systems do not work together. I dislike the power up system for several reasons. There are no extension cables, you cannot build large models with it. The connectors are completely unique to LEGO, you cannot make your own cables or buy them from third parties. There are no rechargeable battery pack meaning you may have to take a model apart to replace the batteries. These elements existed under the power function system, but not under this new system. And this new system really does not do anything that the power functions system could not have done. The Bluetooth controller is cool, it is fun to be able to control your models with a mobile device, but this could have easily been added to the power functions system without breaking compatibility (3rd parties have been offering Bluetooth controller for power functions for a while.) Bottom line: different, incompatible, more expensive, fewer accessories, less flexibility... I do not see much here to like."