I agree with you. These forums are not the absolute source of wisdom.
Normally, my process for considering a lens goes through a number of stages. From the beginning, I had a wide range of focal lengths covered, so eventually, I identify a need for a specific type of lens. For the sake of the argument, say I want a fast 50.
I go to B&H and see what they have on 50s... I get rid of the ridiculously expensive ones and make a list.
Then I go to the Digital Picture.com and look at the optical performance. Lenstip too...
This gives me a ranking order in terms of optics.
Then back to B&H to ask for the help of the audience. I look at the reviews (no I don't read them... yet...) I rank them. From the worst to the best (lower score first). Assuming that I have a good statistical sample, say over 50 reviews, I count how many reviews it takes to reach 4 stars.
My reasoning is that I would not buy a lens that rates less than 4 stars, so let's see how many people rate it as such.
If the result fo 1-3 stars is:
less than 2%, I run to buy it
2%-5%, I set up for a good excuse (like wait for a sale, an anniversary, birthday... and buy it)
5%-10% I put it in the list of 'Can I live without it?' consider it again a bit later. Normally I end up buying the damn thing... I do read the reviews to see if there is a pattern for the negativism.
Over 10%... don't walk, run away from the damn thing...
Sigma 50 f1.4... 299 reviews as of today. 51 reviews under 4 stars 17%. I am not going to be rocking this version of the 1.4.
And I am not Sigma bashing. I have the 8-16 in my signature which I got in direct comparison to the EFS 10-22 one of the most popular Canon lenses.