Scratch is really great - do not get me wrong! But I find it too advanced. They do support various external hardware. And I can highly recommend the Make lock mbot. Truly awesome.
But Scratch is one step up the ladder to me. It is a commitment to an eco-system and a super nice but blank canvas.
I find Logo to be simpler and more limited. This is a "good thing"(tm) when getting kids hooked. The first hit should always be free :-)
I have gotten some of my non-technical friends to buy mbots. They like the idea but the learning curve was to steep for them.