Pogre, my main concern would be in regards to reliability (longevity). (3500 )
Now weather there would be an audible difference or not, I couldn't say one way or another. But sorry to say, the way the transformer is placed directly under the main board, can't be a good thing. And you can disagree if you like, but the heat sinks on the 3500 is also a joke. And that's my opinion, you don't have to agree with it. However I thought it was worth discussing, to give the OP something to think about.
Now as far as your statement regarding a dbt, and picking the difference out consistently. I will never understand why some people think you need to prove what you may or not hear. If someone might be able to hear a difference or not, why should that matter to anyone else. It doesn't effect you. You never hear people say (the one's who might be able to hear a difference on something) to the ones who can't hear a difference, " I don't believe you can't hear a difference"
Those kind of statements are what causes people to not even want to get into discussions about different products. For those who can't ever seem to hear a difference in different products, Great for them. It should make this hobby much cheaper for them. That's why I never dog anyone out for their choice of equipment, if it makes them happy and sounds good them. Well, that's all that counts.