I feel like the masteries taken on Lee Sin should be very simple. Going down the Cunning primarily for is very strong on Lee Sin because of its early damage and the extra CDR from Intelligence . I choose Wanderer and Runic often because as a jungler, especially a non-farm heavy jungler, having the extra movement speed along with having buffs for a longer time is very important for ganking and roaming. I always have on Merciless and Dangerous because the other ones are usually useless on Lee Sin as he uses no mana and most likely will need the 5% missing health compared to the small amount of gold that he gets for giving a camp (ex. giving blue buff to mid laner).
For my secondary tree, I almost ALWAYS go down Resolve due to not only for some health/tanky stats that are very useful on Lee Sin, but because of how I think those stats are more important than the ones in Ferocity . Many people tell me that I should do otherwise, because of Vampirism and its healing affects for Lee Sins W, Safeguard / Iron Will and that it would give extra damage, but the better healing such as from Runic Armor is hard to not take. So for those reasons, I usually take Recovery because it helps him in his jungle clears, but would sometimes rather take Unyielding if the enemy team has lots of scary damage. More often, I also take Explorer because of how I can use the movement speed for better map control and ganking, but would take Tough Skin if they have multiple marksmen and I could use it to help survive. As a jungler, I often take Perseverance over Insight because I don't need 15% CDR on and as I always have wards up with Stealth Ward and Tracker's Knife.