I'm currrently training at HAI. The standard of their training is extremely high both FAA and JAA.
They want their students to pass with high grades and that also counts for FAA students.
European flight schools always like to say that FAA is very easy. Well the helicopter is the same and you will have to fly it. So 40-60 hours of training for your PPL. The theory part might be a bit easier but don't forget you have to take an oral exam as well, and the examiner will find your weak spots. So basically you still have to study a lot.
The total costs won't differ much from the UK but, you fly more in a shorter period of time and when you do the CFI route you will fly about a 1000-1200 hours in 24 months.
If you want to go to Australia I wouldn't get a JAA license. As you said yourself hours are more important and converting FAA->CASA is the same as JAA->CASA.
The last note to FAA versus JAA. When pilots are trained so bad in the US, why is the accident rate compared to Europe so low............