What kind of espresso machine is best for home use?
Home espresso machines are a growing segment of the small kitchen appliance market. A good home espresso machine provides the ability to make high quality espresso in a machine that is typically smaller and less expensive than their commercial counterparts. 

There are three common espresso machine designs for home use: manual, semi-automatic, and fully automatic. As the name implies -- manual machines require direct "manual" control by the user, who typically applies pressure through a lever to deliver the desired brew pressure. Semi-automatic machines require the user to prepare the coffee into the portafilter, but then rely on an automated pump and to deliver the desired brew pressure for espresso. Fully automatic machines automate the entire process end-to-end: grinding the beans, loading the ground beans into the portafilter, and then pumping water through the portafilter at predefined pressure levels to brew espresso. 

Manual machines typically have a lower cost, smaller footprint, and provide the user with more direct control over the brewing process. This allows skilled users to make higher-quality espresso than they would with a more automated machine. In contrast, fully automatic machines are often the easiest to use, but are unable to make espresso as consistently great as a skilled barista could with a manual machines. Fully automatic machines are inherently more complex, more expensive to purchase, and more likely to have longer-term reliability issues. 

Regardless of the type of espresso machine, two factors influence how well they will perform: their ability to manage brew temperature and brew pressure. The best machines provide the ability to vary brew temperature and pressure in consistent, repeatable ways.The type of coffee bean and desired result will impact what temperature and pressure profile the user wants. The best machines offer flexibility along both dimensions in consistent, repeatable ways.