I would assume the following ranking is o.k.
Lemfoerder>>>Meyle with the HD parts and then comes the rest with brand names and then the no names, TRW is also said to be alright.
OCAP is lower price/quality range. They produce in Italy, India and China.
Besides BMA also check FCP, they changed their policy, now have everything from BMW original, Lemfoerder, and the cheaper stuff.
FCP Euro
I just bought from them a OEM front shock for my E36 M3 and they were the cheapest I could find for the same brand/type in the net.