Love this tree. He's the best bottom lane, in my extremely biased opinion. Usually, I'm there, but I've taken him top as well, either is just fine.
Catalyst to begin means I out sustain almost anybody. If they go for the health rune close and snare with W, pass them, then Q, then casually take the health rune instead.
Are they waist deep in your minions? Same deal, lock them into their range as long as possible and watch the little guys tick away the enemy health.
And don't even get me started on turret defense. Ult up and just dare the enemy to try and take it from you.