Quote Originally Posted by ustein
Reason is that owning lenses from Nikon or Canon is not good enough for making a decision. Only true if you own top lenses
If I'm understanding this correctly, then I think I disagree with you. Just to confirm, are you saying that you need top quality glass if shooting with Nikon or Canon DSLR's? If so, surely you would accept that this is another area of subjectivity and debate?

Choose me for example; I used to shoot with nothing but the highest quality lenses (like the Canon ones you mentioned). Eventually I decided that weight was a factor so replaced my entire kit with lighter weight (non-L) glass. I replaced the 28-70L with a 24-85 f/3.5-4.5. I also use the 20-35 f/3.5-4.5 and 70-200L f/4 instead of the heaver options that you mention above. I also use the Tamron 90mm macro instead of Canon's 100mm version although I admit I'd like to own the Canon instead due to the focusing motor and manual focusing ring. I've been very happy with this kit.

Moral; If top quality "optics" isn't your priority, you don't need the manufacturers best lenses.

Trevor