Espresso Machines can be placed in 3 basic categories: Manual, Semi-Automatic, & Superautomatic. Manual machines generally consist of a water boiler and a lever to produce the pressure needed for extraction. Semi-Automatics consist of 1 or 2 boilers and a pump to produce extraction pressure. Manual and Semi-Automatics require a grinder (or pre-ground coffee). Automatics are self contained, grinding, frothing milk, and producing espresso all at the touch of a button.

Semi-Automatics are by far the most popular type of espresso machines. In fact, most cafes use commercial versions of semi-automatic machines. They offer the flexibility to change particular variables allowing you to get the most from a particular bean. At the same time, Semi-Automatics allow for shot-to-shot consistency which is extremely important to repeating good results.

Superautomatics are essentially plug-and-play: Add your milk and coffee beans, they do the rest.  They require a minimum amount of operator control.  These machines are quite capable of producing excellent drinks, but purists will likely be disappointed at the lack of user control over the "fundamentals" that allow the nuances of different different beans to be fully enjoyed.  Superautomatics are excellent choices for offices where minimal user training is needed for drinks to be made.