Oscarus

What is better overall? Slow, bulky pivoter, or fast and very offensive pivoter? 

Should that specific Pokemon take hit, then switch out to other, or switch out as fast as possible, and give it to bulkier Pokemon or someone who resists? 

Oh, I should specify that the specific Pokemon is is pretty defensively built in terms of base stats and typing, but also isn't particularly slow either, around 80 Base Speed. 

I know that this might be a dumb question, but I have a dilemma about the project... the 15th one this day...