Lets get one thing straight....
There is no skills reduction between the FAA IR and the JAA IR. Sure there are differences (both ways), but anyone who is mislead into thinking the FAA IR is an *easy* option should really try and do it. The FAA IR is Nothing like an IMCr, it is a full, ICAO IR - the equivalent of JAR.
The reason an FAA IR is more achievable is:
a) You don't have to wade through 6 months of irrelevant ground school
b) You can train with freelance instructors if you want
c) You can train at your own pace - not just the 1 hour per day some UK FTOs like to do
d) You don't have to have a speceal hearing test from some throw back from before the second world war
e) The requirements to keep it are less onerous - it is easy to maintain at minima cost. Anyone who actually uses it gets to keep it.
Oh and if you do train in the USA, with £ to $ at the moment, it costs very little ($150 per hour inc instructor in a brand new DA40 for example).
In the UK as soon as you mention IR instruction in the UK, the instructor costs jump to £75 per hour - they still get their £15 per hour I suppose......
AOPA UK is not run anything like the US AOPA - if it were I'd join. Their website is rubbish, it has very little useful info on there, other than listing the board of directors (an extensive list I might add), and the cost is high for what you get...Oh but you do get a funky optional Aircrew card to wave at people to show how good you are......
PPLIR on the other hand is a completely different kettle of fish and I am a member....