Team comp alone isn't really the primary factor if those two are your choices. Lee Sin has a bit more risk attached to him since some of his utility was removed. He is generally better if you want to just camp the crap out of one lane really early on as his first clear is much better than J4. J4 is a bit of a safer pick because of his utility. He is also quite a bit easier to use than lee. In the end what I would recommend is playing both for awhile and play whoever you are better with as your first choice. Save the other one as backup in case you don't get your first choice.