As many will say here. It’s only worth what someone is willing to pay and if you are “testing the waters” not many will reply to this thread. Your best bet is to start with a low bid on eBay with a reserve and or buy it now.
Most Miele dealers still sell this vacuum.since its a "dedicated" purpose machine,they are not popular.Have one.Those are not really useful vacuums.They also have a VERY small bag.
It looks like an expensive carpet sweeper to me. People have them listed on eBay from $120-$200 and they are not selling, and haven't for several months.