His ganking is subpar, moreso if the enemy has the type of mobility that renders his slow ineffective. You'll likely be ranking up Consume (to a point) first regardless, so his snowball isn't anything to be afraid of for a while. I prefer 1-8-21 masteries on him due to him being a utility / control jungler more than anything plus he's innately tanky, and I like my runes with 8 attack speed reds and 10 armor pen (1 red + 3 quints) since he'll be using his auto-attacks a lot for his passive. Probably really outdated though since the latter's an old-school loadout and I haven't checked the armor values of the current jungle camps, but I don't feel gimped with that set-up. Could probably also go with runes that allow for him to have 10% CDR at level 1 alongside the 9-21-0 masteries instead, but I never bothered to try it out. I wouldn't recommend building him offensively as a jungler; safer being this glorified tanky support who focuses on objectives and peels for his carries.