With Scratch you are given a limited set of blocks that are designed for a limited set of solutions. It is at the same time not particularly powerful nor does it feel like you can grow your solutions to anything you have in mind.
I have three kids and have taught (or attempted to teach) each of them programming. I started with Scratch every time, but it never piqued their interest, although they understood it. I have since started them on Javascript from the very basics (Khan academy) and they are very curious about each new lesson and the weird powers it brings. YMMV but people should not assume Scratch or Mindstorms and so on are necessarily better learning environments, just because they are 'friendly' - it can be quite the contrary.