I bought all three devices and I'm mixed on what I'll end up doing with my purchase. I love the new keyboard even though I do feel it's a bit expensive. It'll definitely be great not to have to change batteries in my keyboard almost two weeks.
The trackpad and mouse are another story. I was never a fan of the previous magic mouse, but I find myself slowly getting used to it. The last time I used a magic mouse it ended up giving me cramping wrist pain. I'm aware this new mouse is near identical, but I haven't ever used one long enough to decide if I'll gets better over time. I have large hands so I assume that's the culprit of my pain.
The trackpad is a pleasure to use, but I do design work. Although I'm used to using the trackpad on my mbp(I hate carrying around a mouse), I can't help but feel that a mouse makes me more productive. I also ran into some issues with dragging files around with the new mouse. For some reason, I just couldn't do it. It kept deselecting the list of files and I ended up just grabbing the mouse. I'm aware for a three finger accessibility option, but it doesn't work well when you have to drag files across the screen.
I'm currently upgrading from a Logitech MX Revolution. It has aged and the batteries aren't that great anymore. I'm debating on snagging the new Logitech MX Master to give that a shot and see how that work before I make any decisions.
I'm definitely keeping the keyboard, but I'm not sure about the trackpad and mouse. While I really like the trackpad, I don't think it's worth spending the money to have two devices on my desk.