Good quality macroline should not burst up until about 1500-1800psi. That would be achieved by leaving the marker gassed up with CO2 and left in the sun. Steel hose would be more durable over the long term, but it is more difficult to get it in place and to find in the right length with the right threading.
If your friend is really having problems with inferior quality macroline, then he should order a few from The Macroline Guy. He backs his stuff to never burst under normal circumstances.