As i understand it, you do not train for the FAA CPL, only the FAA IR, then convert that to a JAA IR, before going to the 15hr CPL course for IR holders...
it is all very well saying dont train in the US, but different people have different requirements - for example you need to pass quickly and cant afford to be waiting for wx.
it is also worth noting tht big schools like oxford train outside of the uk (yet still charge uk prices!) so its difficult to make an argument based on airspace/atc etc. the thing to remember is once u get on to your a380 u wont care abt wether u can fly vfr from one town to another on compass and stopwatch!!