According to Apple, the Magic Keyboard, with usual use, is expected to be able to go up to one month or even a month and a half without needing to be charged. The keys have even more features, but they last for a shorter amount of time, as Logitech indicates about 10 days with smart illumination on, and about 5 months with it off. The MX Keys has a low battery warning system that the Apple Magic Keyboard lacks. Should it be the case that the battery is a primary concern, it really depends on the features you require and how often those features will be used.