I found this video on the _This Old House_ website
http://www.thisoldhouse.com/toh/video/0,,1631516,00.html
that details how to make fittings, notice that there is no soldering needed. In addition to that benefit, piping runs can be single lines without joint in your walls, eliminating joints, or points of failure, from being buried in your walls. As you’ll notice, the piping runs become can be laid out much more like electrical wiring this page from Lowe’s has some more detail on that.
http://www.lowes.com/lowes/lkn?action=howTo&p=Improve/PEX.html