I don't know what the Flashpoint Miniatures scale best with, 15mm isn't really my thing these days but I have seen the figures. Fairly crude sculpts, spindly with massively oversized weapons. I'd guess the figures would go at the ankles before the weapons' barrels bent. If they were 6mm figures I'd give them a grudging pass mark. None too historically accurate either.
On the whole the vehicles are much better although, ironically, the 'Australian' M113 is awful and sod all like the T50 turreted item. The Battlefront version is the pretty much same thing IIRC, at least they are both wrong on terms of the turret, hatch and rear hull ventilators. The latter two could be remedied with plasticcard and a file. At least they do provide the option of the M74C turret which was the pronciple version from late 1966 to late 1968/69.
I'm yet to see a 15mm Vietnam range which I'd spend any money on. YMMV of course.