I saw some horror stories with Tamron. Three lenses of the same model all from the same batches that produced three different qualities for a same picture. I think it was on the Pictureline website that I saw that article.
I saw waaaay too much of those stories on Sigma/Tamron/Tokina lenses compared to very few people vouching for them. The 120-300/2.8 and for the 150mm macro Sigma are pretty much the only ones I saw people actually saying they're better bang for the dollar; compared to Nikkor. I dont know much about Samyang; other then they're made in Korea.
As for Zeiss, well, its Zeiss. Its kinda-aside.
I always picked Nikkor lenses because if you shop right, you recover pretty much 85-90% of your money when you decide to sell. And if you shop right in the used market, you can even end up making money on them.
Last edited by MaximusJ; 08-17-2012 at 03:00 PM.