what constitutes a "fat burner" as you say? what do you speak of?
you compare a singular ingredient (caffeine) to an entire sub-category of products.
"fat burners" are a general topic, with many different structures and compounds.
is caffeine "the best" if you want to "burn fat"?
quite simply - no.
can caffeine be a useful adjunct in fat-loss goals?
sure. ECA stack is considered by many to be among the best and simplest options out there...
can all ppl use caffeine or tolerate ECA?
if you don't like the idea of "fat burner" products, don't use them.