The PGM and RGA are different guitars so "better" is completely subjective. And the type of music you play would be relevant as well. The PGM has a PAF in the neck and bridge so a
Tone Zone bridge and PAF neck in a RGA is going to sound different anyway. Also, since the RGA has a mahagony/maple cap body and
rosewood fingerboard vs. basswood body and maple fingerboard on the PGM they are going to sound different even with the same pickups in them because the woods are different. The bridges are also different.
I think the rep might be on crack because the Ibanez Japan site shows the necks to be the same dimensions. Maybe there is someone on here who has both who can comment or maybe the Ibanez guru himself, Rich from ibanezrules.com will weigh in but I believe they are exactly the same except for the maple fingerboard on the PGM.
I don't know about the half down business you mention or who you'd be buying it from but if you buy from many internet stores they will give you 30 days to return it if you don't like it.