is it better to

is it better to hang the whole plant in 1 peice with all the leaves/bud on it to dry out or is it better to cut it down and dry it out by branches

You'll never be able to tell the difference either way so do what is easiest for you.

its jsut more practical to cut ur branches off to trim the leaf off, but if you weren't going to trim id say just cut it at the base and tie it upside down to dry
also most people cut it up to get more air circulation (the closer a bud is to another one the more Chance of mold etc

I leave them on but cut off only the big fan leaves and water leaves.