If you want to get an unrestricted FAA PPL (it's not mandatory) before going on to the IR, you will need to ensure that you have all the required flight experience as documented in FAR 61.109
You will need to meet ALL of the requirements for the FAA PPL and the FAA IR to take the IR checkride. I got caught this way, I didn't have any night and came to take the FAA IR checkride (on a "based on" ticket) and the examiner "failed" me straight away
Advantages of FAA ticket:
Much easier to keep. In Jarland if you don't jump through hoops at exactly the right time, you can loose your ticket. Last year, despite having done about 60 hours in 12 months I almost was forced to do a retest. This was because I didn't have the "1 hr with JAA instructor in last 12 months" element. The weather was bad for weeks and in the end, luckily, with 2 days to go I managed to get up for an hour - only beacue it was blowing about 35 Kts and the examiner I went with had cancelled his PPL student. I had deliberately left it this late because the CAA in all of its wisdom says that you must get the licence signed by an examiner but only in the 3 months prior to expiry! How silly is that, if you meet the requirements 1 day after year 1, then why not get your ticket singed then, and valid for a further 3 years? This is what I did do in revalidations 1 and 2.
If this happens in Faaland, you are not allowed to fly, but you just do the Biennial check when you can get time....no big deal.
Not only that, but every 5 years you have to re-apply (and pay) for the JAA licence.
The FAA are realistic with regards to medicals. This may or may not be an issue of course, but medical duration is longer. A class 3 is valid for 3 years at the mo, due to be 5 years soon (sub 40 yoa).
One of our group members flies our G reg quite happily on his USA certificate. Has done for years, and insurance is not even an issue.