BigGrecian's method is formally defined in
14 CFR 61.75, "Private pilot certificate issued on the basis of a foreign pilot license." The alternative of completing a standalone (
14 CFR 61.102 - 107) may prove more convenient in cases where the 2-week wait is undesired, etc.
Some extra training is required (notably the night rating requiring a 100 nm navigational exercise leg rather than 1 hour and the requirement to have completed 3 hours' preparation within 60 days preceeding a flight test, in addition to the theoretical knowledge exams) but a BFR (14 CFR 61.56 "Flight Review") is not initially required. The certificate itself does not expire; a separate FAA medical certificate is required; a TSA security threat assessment is required; a vocational student visa is not required (contrary to popular opinion).
Weighing these factors the 'foreign-based certificate' (§61.75) is likely easier and cheaper although bear in mind the approval process must be undertaken each time the underlying JAR-FCL licence is modified (ie, exchanging JAR PPL for CPL, etc).