Both types of fuel will get the job done. The main difference between the propane and MAP is that the MAP is hotter. What that translates to is you will heat up the pipe quicker allowing you to solder faster. If you can heat up the fittings quick, you will actually be heating up less pipe area which can make things better when working near valves. Also, since lead based solder is not code compliant for domestic water system, the tin and silver based solder take a little more heat to get them to flow and the MAP gets the job done quicker. There needs to be caution exercised because most torch heads designed for propane are not compatible with MAP gas unless clearly indicated on the torch head.