Personally I don't think it matters as much as he says he does. There are one or two airlines that I am aware of that says that you need to have experience flying in Europe (Monarch I believe is one of them). Being a airline pilot myself I can tell you theres a big difference in how you fly during training compared to in the airlines. Being a airline pilot becomes more of a system monitoring position, you fly IFR everywhere so such things as VFR chart navigation or entering patterns and airspace requirements etc aren't as important as they were before.
Thats my opinion tho. As for training being better in the US or in Europe, it all depends on the school, theres fantastic schools on both sides and slimy money grabbing schools as well. Personally I think cost is lower in the states, the weather is typically better (florida) and its obv a nice experience getting away from home and being able to say in your resume that you've flown abroad.