For ex/rare, rare items (green, light blue, purple) I believe it will be bound to your character. But will this also apply to those items that has multiple materias melded onto them?
From reinharts thread (see op's link)

I would guess that it would only apply to things like sentinel gear or militia accessories. greens light blue and purples etc.

it still kinda sucks though as alot of gear i buy i tend to typically experiment with. in a type of is this pair of pants better than this pair of pants or is this ring better than that ring style scenario. i'd hate to spend loadsa gil on something only to find it is actually inferior to what i had previously.

if it was limited to green / purple style stuffs then it could ultimately make them inferior to crafted. for example a pair of cobalt gauntlets could end up holding more value than a pair of sentinels even melded options. as you could resell the cobalt when you upgraded to recover some of the upgrade costs but the sentinals would be worthless