A tale of battery cables

KitCarlson is right on about potential problems with soldered connections. If only a small amount of excess heat is applied, the solder wicks up the wire, often inside where it's not visible. That point is the weakest part of the wire and even minor vibrations work-harden the strands so they break easier. This was a severe problem with early spacecraft and bad solder joints caused many catastrophic failures. Responsible manufacturers made sure that all solder joints were carefully inspected, and NASA operator certification was required for anyone making a solder joint for their programs.

Info for the DIY folks: it's also critical that you use non-activated solder. If not, corrosion will begin immediately.

If you really know what you are doing, solder is fine, but if done by someone not properly trained, it will fail long before a good mechanical crimp.