Fun, and not hard to get started with (though a look at the manual will probably help!).
(Also, note: if you also check out the Bliptronic 5000, and have a couple cables with male miniplug cables on both ends, you can try to sync the two. I could only get it to work well with the monotron set at an extremely low tempo and the Bliptronic at one of its highest. But the results could be kinda fun.)
Turn the volume all the way up and march around your house playing "Scotland the Brave". It'll make your day.
Doesn't annoy the family as much as synthesizers that make noisy hard-to-tune sounds.
Takes about 10 seconds to boot, unfortunately. Once it's running, choosing a sound and playing is easy. Recording loops seems easy enough too. Fooling with the effects looks hard without the manual in hand (though there may be no real reason to do that.)
The clip makes it easy for two people to play at once.
Maybe playing with a stylus just isn't very satisfying.
But someone else might have better luck with them.