I often think the two primary reasons for these types of questions are i) laziness, its just easier to type a question and wait for a flow of responses and ii) many of those asking that type of question would probably be unable to evaluate the results of a comparison in any meaningful way themselves anyways (ie beginners or never really serious types) so they just ask others, knowing that now, they are using "the best".
Additionally, another associated issue with many of the "which is better" questions is that people are assuming there just IS a best one. No one ever asks that question with a criteria against which to evaluate better...
...but, then again, thats just the Internet :bang:
Just continuing to think about this topic and realised that Im probably even guilty of doing this myself in non photographic areas. Whether its about hard drive manufacturers or home theater speaker system and for me, asking that question is (apart from I dont want to buy of of each and try it), I admit, I dont really know what response Im trying to elicit when I ask a "which is better" or "what is best" question - is it drive fail rates, customer service or importance of a feature - Im just hunting for info and to get a feeling about the product in use! For something like a home theater speaker system, Im trying to get a quick education on general opinions. I don't care too much about it - to me its just a sound system for a tv - but I do want to know something before I enter the store and get led around by a sales guy.