^ Yes they're one of those items that tends to fetch a standard price on eBay now. IME, the only bargains are in the classified ads on the secondhand sites where people don't always know what the standard price is.
One stone in dozens and dozens of kilos of beans and they gave me loyalty points equivalent to the cost of a new grinder - but no names, no pack drill.
Interesting. I wondered about the Ethiopian link because Mazzer sell a magnet to hang in the neck of the grinder to catch the ferrous stones found in Ethiopian batches. I wasn't sure whether stones were more usual from that region or if theirs were the only stones it could pick up!
I scoop beans out into a thin metal bowl before they go in the grinder and just hope I hear the change in sound.
I ended up buying a 2nd-hand Baratza Encore on ebay. Got a good price too at $60 (about 40 quid). Got it cheap because the seller didn't bother cleaning it and it looked in the photos like it was used to grind pig sh!t. Spent an hour giving it a thorough teardown/clean and it looks brand new. Does exactly what I want it to.
My Krups is for sale (now sold) if anyone wants it. Only used about 5 times, pretty new-ish. It grinds fine enough for espresso, but excels for automatic drip machines. I'll probably list it in BST this weekend to sell or trade for shaving crap.
It's working great. Nice and quiet and grinds very quickly. I've been tinkering with the grind and I think I get the best blend on grind number '25' on mine for the pour-over steel filter. Very minimal 'muddy-ness' in the bottom of the mug. Very happy.