Generally resistors base pre will have more dynamics and midrange than transformer pre. but transformers will outshine in areas like transparency and detail, just my 2 cents. i think it would be hard to notice their musical differences between the two if they are both well design, you need to strain your ears to hear the differences, i guess.
BTW, are you sure Dude has transformers in signal paths?
BTW, are you sure Dude has transformers in signal paths?