Talking this out. It applies to my decision to go multiple attack or vital strike with my alchmist/visectionist. I'll probably go master chymist eventually, but I want to enjoy the first few levels as well. With multiattack and sticky poison and hopefully sneak attack would be fun, I'm just concerned that I'd get bogged down on my turn and keeping track of everything. Plus I'd need the greater magic fang for all of my natural attacks. Vital strike seems cool, and I'd probably dip into barbarian for furious finish. That seems a little simpler and straitforward. I won't retitle, but how simple/complex do you like to make your character's combat rounds? I already decided to go melee with my alchemist as figuring out where the bombs went if they missed and splash damage was a pia.
diplomacy :
I don't generally find keeping track of multiple attacks that difficult. Especially with something like a Bite/Claw/Claw combination, they are going to have the same (or close to the same) modifiers. You can even roll three dice at once (using different colors for claws and bite) to save time. Things can go complicated if you go nuts (Rapid Shot Two-Weapon Fighting throwing with Deadly Aim... oy), but a simple natural attack Alchemist shouldn't be a problem.
From a mechanical perspective, Vital Strike would be the much weaker choice for this character. It provides more benefit with weapons that start with a large damage die, which Natural Attacks and weapons the Alchemist is proficient with don't provide. Sneak Attack benefits greatly from multiple attacks, especially multiple attacks with high attack bonus like natural weapons. It doesn't get multiplied by a Vital Strike, so is less useful in that situation. Your base attack bonus also won't be advancing that quickly, which puts you behind the curve on higher level Vital Strike feats (not to mention using so many of your feats on it). If you like the simplicity or the mobility go for it, but going the multiple attack route would, in general, be much stronger.