I think it depends on your objectives. What abstractions are you trying to have your kids develop?

* Are you trying to teach your kids simple blinky-light programming?
* Maybe you want them to develop into C++ coders?
* Do you want your kids to understand underlying computer architecture constructs (bits, bytes, cores, caches, etc.)?

I learned LOGO as a 7 year old & Lisp shortly thereafter. Later we got a TRS-80 w/ a built in BASIC interpreter and out of a mix of necessity and curiosity taught myself Z-80 Assembly and eventually started playing around with ALUs & 7400 series logic on breadboards.

My offspring isn't interested in the low level details, but was VERY interested in making art on the computer. We started with MS-PAINT-a-likes, moved on to Gimp & eventually to Blender, using Python to automate some processes.

So... my advice is to think about what you're trying to accomplish. If your kid is interested in low level stuff, maybe start with a soldering iron. If they like art, think about the tools they'll use to model the abstractions they want to work with (Gimp, Blender, Maya, Adobe CS, etc.) and then look at the languages that are easy to integrate w/ those tools.

Also, remember that modern spreadsheets are a powerful data-flow modeling system.

Modern educators tend to follow the Constructivist model, a simplification might be: "Give your kids some tools and see what they do with them, possibly nudging them towards techniques or solutions when they identify a specific intent or goal." Constructivist educators would probably tell you the interaction between the learner, the educator and the tool is probably more important than the specific tool.

Constructionalism takes constructivism a bit further and seeks to support the creation of mental models and abstractions by the learner. LOGO, eToys & Scratch were built by teams that were largely influenced by Seymour Papert & his constructionalist ideas. In education circles, there's a little bit of debate over constructionalism, but it's definitely produced some great tools. And heck, I've had a pretty decent career as a software engineer, so learning LOGO at MIT as a 7 year old in the early 70s seemed to have worked out well for me.

I'm personally less of a fan of Scratch than I am of TI LOGO running on an old TI-99/4, but that's probably because I find Scratch MUCH too cluttered. But YMMV. Scratch is definitely worth checking out.

So to sum up my advice:

* try a bunch of things to figure out what your kids interests are.
* understand the tools you present your kid(s) with so you can help solve problems when they're blocked.
* show your kids a few simple things and let them discover the rest (and then unblock them if they get in a jam)
* if your kids are mentally checking out, it's time to try a different approach.
* don't be afraid to let your kids "waste time" on things they enjoy, even if it doesn't immediately seem like they're learning something (my offspring knows boolean logic ONLY because we found some youtube videos about redstone circuits in minecraft.)

Also, you can buy a copy of Papert's "Mindstorms" book online (or heck, it might be available as a free download by now somewhere.) It's a tiny bit controversial in education circles, but it's relatively short and it's a decent intro to Constructivist ideas.

So... all that being said... I was pretty impressed with how cheap & fast it was to set up Scratch on a RasPi w/ Raspbian. Under $200 even with a new mouse, keyboard & video screen.

The LEGO Mindstorm products all seemed to be a little overpriced to me, but if you don't want to spend the afternoon hobbling together a cheaper educational robot system, they're probably not that bad. Seymour Papert was really big on getting kids to interact with physical objects, so if you buy into Constructionalism, this is definitely the tool for you.

I'm a fan of the LittleBits electronic toys. My offspring ignored them after five minutes, but I've seen other kids spend hours putting blinky light creations together w/ them.

If you're handy with a soldering iron, it's a snap to put one of these pencil circuit tools together. I personally love it. My offspring liked it for a while before disappearing into the purple cloud of sullen adolescence. It was also a bit of a hit w/ my niece.

https://makezine.com/projects/build-electronic-audio-game-pe...

I tried to make sense of the Dash robot, but honestly, I couldn't figure out how it was supposed to be educational. YMMV.

Ditto for Cubelets. At $26 per cube, they were a little pricey for a system that seemed to come with waaay too few instructions.

I really want to try the makeblock drone airblock system, but I'm probably projecting my own desires on this one. Still, I used an early version of the makeblock neuron system and it was at least as good as the littlebits (though littlebits in-box documentation was better.)