Technically, wrapped and crimped joints are , when done correctly, superior to soldiered joints, soldered joints, as mentioned before, can become crystalline, and make the wires brittle, the bit that is vapour tight on a crimp is the metal to metal contact caused by the pressure from the crimping tool, you will never get this with pliers and moisture will get between the surfaces eventually and start to cause problems, if you decide to keep using pliers and or solder I would recommend that you augment it with glue filled heatshrink sleeves which will help to keep out moisture as well as help stop the wire flexing at the joint.
and if you are an inexperienced solderer then this is the stuff you want, solder
Tim
Edited by - tbird on 7 Jun 2013 22:25:12