from a programming point of view, all are the same.
But if you want to introduce your kid to play with sensors and other stuff, I'd get Playground Blefruit[1]
maybe an arduino board plus a raspberry pi?
Arduino's are lower-level C/C++ which may be a little more complex than CP, but have much broader library support (better intro to EE/embedded).
RPis are much higher level which could be programmed in any language (better intro to CS/Linux).