Braided SS vs. Hard Line

In general, with brakes, use flexible line only where neccessary.
-3 has less expansion under pressure (than -4) but that's mostly a concern for road racing and otehrs who want maximum brake feel.

I have had -3 brake line fail. Happened just at the end of driving down the east coast to Pensacola. Fortunately that's a location where its easy to have new AN lines made for you.
I do not know if the failure was due to the crimp, or slightly (1/2") too short creating a too tight of a radius, or slight twist when I installed it. All of the above are reasonably possibilities.