Of course they are.
If you want to fly in U.K or European airspace, then learn in that environment. If you are going to fly in the states then learn there. The procedures we all fly are different, not better or worse, just different.
To be honest if you add it all up, learning to fly in the States is NOT cheaper than here in Blighty, if you include the cost of re-training, I've never had to do "just" a check out. The fact that in many places across the pond you have to pay for ground briefings. Then add in flight and accomodation costs. All of a sudden the U.K is not quite as expensive.
Most people only look at the per hour rate and while there is a massive difference that is only part of the story.
I'm not going to get involved in the "we're better instructors than them" argument because frankly it's bo**ocks.
However as I've already said if you are flying in the U.K it is alot more sensible to learn in the U.K. You won't have to relearn our procedures when you get back and relearning something is alot harder than learning it initially. No bad habits as such...