Dear All
I have just ordered Canon 400mm F5.6L lens for wildlife and bird photography , but when i am done after my ordering now , many were saying in different forums that 300mm F4 is better in IQ than 400mm prime.. Is it ? I checked with my dealer and he said that canon india has already shipped my order and now i cant change my order

.. Can anyone please pass on some advise to me ? Is canon 400mm prime good lens or did i just messed up completely? Price difference between two lens is around $200

(my wife will kill me , if i upgrade) but i really wanted to know your suggestions/advises soon on this.
Desparately waiting for your replies...
Regds
Mano