Should I buy dry compound mix and mix my own? Pros/Cons
My "drywall guy" (and the pros on construction sites) uses all pre-mixed compound in buckets.

Green lid for applying tape, blue lid for top coats and spotting screws.

He did say you can get 20 minute or even 5 minute dry mix and he has used these for very small repairs when you want the mud to dry extremely fast. These products have extremely short work times so you really have to know what you are doing. 

So, like all things, there are products for specific tasks and the size of your job. Make your choice accordingly.

Good luck!