Keep in mind that this is a build that works for me as a player. Make your own tweaks for what works for you. Example if you don't burn a lot of mana, you can substitute insiatiable with Thick Skin (giving you that extra second to get out or get a kill shot) or with Eyes in the Dark (if you wan't to disrupt and confuse) at Level 4.

At level 13 you could sub On the Prowl with Running Wild (for more effective dive/escape) or Unfettered Assault (for more punch and cooldown on the Razor Swipe)

These 2 subs doesn't effect the mechanics of the combo, but the definately the speed and mana-burn of your combo. Again it is to find the build that works for you and you can adapt depending on the map and your team comp. I sometimes go the stealth option just to reveal a Valeera or Zeratul while in a team fight, which means that for 3 seconds they can be targeted by abilities that can't target them when they are cloaked.

Hope that helps a bit. - Keep in mind when you are picking a talent, ask yourself what will this talent add to my other talents and then to your play style (aggressive, passive, defensive, etc.) and above all play to enjoy, your build should make your Hero FUN to play with.