It actually depends on how you want to analyze the selected data. Hit based data makes sense when you are only looking for total instances vs visit/visitor based data makes sense when you look for visit/user-based calculations in place of the total hits. Ex. If I look for the total unit sold for an item than hit based data makes sense but if I look for units sold per visit/visitor than its a different story.
However, hit based clickstream data export (data feed - A defined set of parameters and values used to collect a set of data.) is the safest bet while if you need to calculate hits by visits/visitors than segment export (data warehouse) can help.
