As far as "character", The Triad is still seen as more blue-collar, while Charlotte is seen as more of a "banking/business" city and the Triangle is Tech/biotech plus home to 3 good universities. There aren't really any "accent" differences between
natives from the three places, though of course all three have many folks from other areas, so you will hear many accents. There is a difference between NC natives who grew up in cities vs. the rural areas (but isn't every state like that?).
Charlotte and the Triangle are more white-collar, but be advised that competition for jobs in NC is perhaps the highest it's ever been, with so many wanting to move here even as the number of jobs is reduced by layoffs and hiring freezes. What industry are you specifically interested in?
Crime varies so much between specific areas of each metro, that shouldn't be a deciding factor of one metro over the other, since all have very nice places and ore crime-ridden places.
Charlotte is the biggest "city" as far as downtown architecture, etc., but you would really need to visit and check them out, if this is a deciding factor for you.
The Triangle is probably the "Bluest" area politically. But NC overall is a "Purple" state with some oxymoronic political outcomes sometimes.
Is there is a reason you are interested in "NC" but don't seem to know about the cities themselves? How do you know that a different state might have more of what you're looking for? Usually people come becasue they like a paticular city that happens to be in NC, as opposed to picking NC but not knowing where they want within the state.
You can look up basic info on the cities in NC on
City-Data's main NC page.