I've been living with the MicroMemo for a few days now and overall I'm very happy with it. It's not perfect, but for the price it's a decent tool.
On the plus side:
1) It's tiny and powered by the iPod so it can go anywhere you go
2) It's simple to use, just plug it in the bottom of your iPod and it's ready
3) You can manage recordings (ie delete crap ones) in situ
4) The bendy mic makes placement easy
5) Recording quality is decent with surprisingly good bass/treble
On the other hand:
1) The switch from 'mic' to 'line' to 'earbuds' is terrible
2) You can't download memo files without going through iTunes
3) Other than by selecting 'line' or 'mic' there is no volume control
4) There is some hiss on the mic
And the stuff I didn't really care about one way or the other:
1) The built in speaker isn't great
2) The side button which does something, but I'm not sure what
3) The supplied mic is mono...
4) Once the MM is plugged in nothing else can be
5) There are two sample quality settings
I'd definitely recommend it for anyone who wants a decent quality mobile digital recorder. It basically does what it says on the box and it does it surprisingly well.