Lipper is correct about the differences between the two experiences.
Now, as for the prestige question, you seem to basically be asking which will be better for your future job prospects. For post-graduate clerkships, the answer is pretty clearly a federal district clerkship over a bankruptcy clerkship. For a summer internship, I think the answer turns more on the level of "connectedness" of the individual judge. Which judge has more contacts or more leverage in your desired job market? You could find this out by asking attorneys in that job market which position they would seek. My baseless assumption will be that most attorneys will say work for the district judge, but there may be situations in which there are very connected bankruptcy judges out there.