I don't own either one, but I have read every thread I could get my hands on. Both Meile and asko are well built machines. Asko used to have a lot of problems but more recently they seem to have resolved them. They are solid stainless steel: interior, exterior, and all racks. Their tall unit will hold an enormous amount of dishes and the only problem with it is will it fit in your cabinet space. Meile has a lot of believers on this forum. They too have had some recent quality issues reported by owners. You should search this forum for leads to the issues. There is another forum where consumers report issues but I can't recall which unless it is Consumer Reports online.

My Miele dw is 13 without any repairs so no quality issues in this case. I've had two of these and really love the quality. Wouldn't buy another brand.

That said, Asko and Bosch have many fans. It really depends on preference, features wanted and of course, budget.