Now, with natural color I'd definitely have gotten the AA+ as opposed to AA. In dyed the blemishing is less noticeable, though Terry's are probably better AA than most others out there. There will be the odd pearl here and there with a few pits but your eye tends not to notice in darker colors, and the moderately blemished pearls are much rarer than I'd expected. The luster is also mildly less than in AA+ but I suspect they might have undergone just a tad more treatment than the usual though I can't be completely sure. They still look gorgeous in natural light in a different sort of way to lighter colors. In natural diffused light the light colored pearls tend to pop even in the AA+ grade, while it's more a soft glow with the AA which appears just a little muted. Probably why it's a waste dying AA+ and higher grade pearls cos' the luster just never ever shows up that well.
I don't find much difference in shape between the AA and AA+. Even for higher grade dyed AAA there are a few that are slightly off-round especially towards the ends of the strand, though the matching and graduation are done more smoothly. Shape is almost the least consistent between the grades as far as my eye can see, but I'm very picky and I've been very happy with both surface and luster for all the strands so far. My fav is still going to be the freshadama - nothing will ever beat that - perfect spheres or near metallic luster with depth. Unfortunately there cannot be dyed freshadama, and I will eventually get Tahitians for darker colored pearls. Eventually.
All in all I'd say definitely AA+ and above for natural colors.
ETA: For dyed I'd probably just get AA+ rather than AAA. The luster is better in AAA, but it's not as noticeable as in natural colors. Better value for money.
