Atterberg is a much more considerable figure than Borresen IMO. His 2nd and 3rd symphonies are my favourites; the 3rd in particular is one of those works so emotionally overpowering I can't listen to it too often.
Indeed! Borresen was a minor composer; his music is enjoyable but doesn't have much staying power. That said, there are many good things to be found in his Symphony no. 1 and VC. Atterberg, on the other hand, had a masterful command of the orchestra and poured his heart into all of his music, producing glorious results. His 2nd and 3rd symphonies are my favorites as well, along with the 5th. I agree with you about the 3rd-the finale in particular is so deeply overwhelming that it can bring tears to my eyes :) Only very special music can achieve that :)