Burr Vs Blade Vs Factory Ground Coffee Beans
BLADE
Pros = cheapest automatic option, almost always uses an electric motor.
Cons = non uniform grind can result in sub-par espresso extraction, also the smaller particles can gunk up the filter basket creating a complete block.
BURR
Pros = comes in manual and automatic versions and produces a perfectly uniform grind.
Cons = hand-grinding is effort intensive and can take a significant amount of time to yield a small amount. Electric powered burr grinders are the best, however often come with a higher price tag.
FACTORY GROUND
Pros = ready to go! Comes in large quantities.
Cons = pre-ground coffee is prone to oxidation due to air exposure, this yields a sub par coffee extraction in both taste and crema; freshly ground beans of the same type will always produce a superior shot of espresso.