And in my experience not nearly as good as they're cracked up to be. Designs may be fine, but their production engineering leaves a lot to be desired. What CAN be said for the Bosch group and can't be said for most other makes is that spare parts are readily available from Bosch, on the web, albeit at a price.
Miele are generally well-designed and well constructed, but they're a horrendous gamble in that spare parts are priced at hundreds of pounds and vital information is often not available. In some instances, it's a case of buying some parts on ebay from German servicemen who rebuild circuit boards. Possibly the best answer is to buy a bottom-of-the- range Miele where at least the chances are that you have the pleasure of using a nice machine and a good chance that it will last a long time while if it doesn't, then at least it's not thousands of pounds you're throwing away.