So far as I was aware an FAA certificate holder has for many years been entitled to fly a G reg aircraft on this ticket. I understand the CAA will issue on IMC rating on the strength of an FAA IR but the rating has to be issued. I was not aware of any changes but would be happily corrected.
.. .. .. but the the question is - is the JAA PPL dead?
The training for each ticket is much the same, both can be done either here or in the States so for both the advantage of cheaper fuel State side can be secured, so surely it is horses for courses. One exception - the FAA IR certainly requires more work than our IMC, so for some the IMC rating will provide a more achievable additional rating.
Horses for courses then but the FAA ticket may well prove cheaper in the long run with the more relaxed medical standards and it being a ticket for life with no renewal fees.