BC are rebuildable, they have a pretty good warranty from the looks of them.....
I currently have Teins but will remove and sell to someone that wants to rebuild the rears and have a nice set of coilovers. Of course the brands mentioned are cheap and arent going to win you any WTAC events but they are decent value for money, my reason for changing gets laughed at by all but its true, i dont want bright green and blue suspension as it just attracts defects, the fact the BC's are black are half the reason for choice but its just less obvious.
I have driven cars with Tein (mine) and others with BC's and if they are set up right i find them to be similar.
It comes down to personal preference and use i guess