They're amazing. I have two (and three inner pots).
I use the timer to soak oats and water overnight (in a bowl on the trivet inside the main pot) and my daughters wake up to hot porridge the next morning.
Chicken thighs cook in 10-15 mins max.
Stewing beef/lamb/pork cooks in less than 45 mins.
Huge joins of pork shoulder/gammon/lamb cooked to melting apart in 1.5/2 hours rather than 4 or 5.
Beans/lentils are super-speedy. Veggie curries quick and easy.
My favourite function, though, is that it automatically switches to Keep Warm mode when cooking is finished, so it's sitting there ready for you whenever you want to eat. (I love my rice cooker for the same reason).
Haven't got around to making yoghurt/cheesecake in it yet (probably a good thing), but it also steams Xmas Pudding in a fraction of the usual time.
After seeing mine in action, my mother and three of my sisters have bought one too, and my last remaining sister wants one for her wedding present! They're fab.