Try it! Make big prints from both and see which you like best.
With Delta 100 I can make 16x20 prints from 35mm that looks very smooth and with very little grain. I don't like those prints very much.
I don't use Delta 400 much, but when I use TMax 400, or even Tri-X, I like my bigger prints much better, because of the grain providing enough texture to make it interesting to me.
This is a very personal thing, and should not be taken as an absolute. Just use what you like best, because that is what will be more satisfying to you.