Blank keys are no problem for a true touch-typist. If you want to try out whether you'll have big issues, try programming in the complete dark and see how much you have to search for the keys. This is a very personal issue; I personally don't have an issue with blank keys, but most people having to use my blank keyboard do find it difficult.
As for the DAS Keyboard, I don't have experience with this exact model, but due to the high build quality and the use of true mechanical switches with damping, it should remain completely quiet for its lifetime. Just remember that only diamonds are forever.
Keep us updated if you do end up purchasing this model!