Canon 70-300 IS USM vs 70-300 L IS USM

have this lense, and this completely contradicts with the results I'm getting.

cant follow your logic. So why not using the 200mm L instead of the 70-200 following this logic. Test I saw claimed the 70-300l is still better at 300 than the 70-200 L II with tc. While the 70-200 is an awesome lens, this combo is completely BS looking at the OP price and weight requirements.

to the OP: had the 70-300 non L, and disliked the contrast at 300mm. Now have the L, which clearly is one of my favourite in my bag with some other L's... If you can afford and lift it, go for the L.