This is the way I (and many others) like to put it: The best lens is the one that's available to you now.


The current super telephoto lenses are simply outstanding in terms of their image quality. They are super sharp, all are very fast for their focal length, and they focus "just like that". You can't go wrong.



Think about it this way: If you were to wait until the "potential" release of new lenses, imagine all of the photo opportunities you will miss just to get an improvement over an already superb line of lenses.


I would suggest just going for it. The lenses you are considering are simply outstanding.