I have been through both the JAR/FCL and the FAA medical.
There are some differences between the 2.
Rumours said that the FAA test was a "joke" compared with the JAR/FCL
In my case that is not true.

JAR/FCL : Takes place at flymedisinsk institutt at blinderen, Oslo. Price app. 4000,-
You will get the result after app. 2-3 weeks
It is true that this is a more extensive test.
- Requires lung X-ray
- Requires a " funny brainscan"
- Ekg heartscan
- Complete audiometric test ( They measure up to 8 Khz ). Mine was 8 / 7.5 Khz
- Complete vision test. ( You can pass with max. -3.00 correction - class 1 )
Mine was 1.2 / 1.2
If you had refractive surgery ( LASIK ) you must wait one year before this test.
- Body composition ( fat - muscle water etc. )
- Other common medical tests.

Takes one whole day, and I reccomend doing this one before going abroad
...just in case.

FAA : This one is more straight forward" old fashioned " I paid 80 US for a class 1
You know the result straight away.
- Vision test slightly different than usual, involving an instrument you look into,
nevertheless does the same job, and I got 20/15 - 20/15 ( 20 / 20 is normal )
- The rest is common medical testing, takes 30 minutes, and you do get tested pretty good....

If you are in normal good shape, you will probably pass both.
I would do the european test before going - if you pass this one, you will most likely
pass the FAA test as well.