You cannot do a JAR IR in USA, it has to be in a JAR state.
Some training can be completed in the US just a minimum must be completed in JAA airspace, including the test.
Some schools offer 25 hours single and 5 hours multi then the rest in the UK. This does conform to JAA. 10 hours multi and sim in the UK.
Spain is best as cheaper than UK.
Spain is also a lot lower quality.
I.e Easier. The airlines and employers (even potential FI employers) know this.