I would say that for heating and brazing, but not welding, oxy-propane should be good enough. Mine is likely not really a large enough flame with only 5 litres/minute of oxygen available (about 88% O2, so not sure if it is 5l of oxygen or 5l of gas per minute).
My oxygen supply cost me less than a couple hundred about 3-4 years ago. Never runs out, no rental of anything. Twice the size would likely be far better than my 5l/m supply.
I suppose butane would give a hotter flame (more carbons and fewer hydrogens), so better still.