Espresso machines preserve the natural flavor and aroma contained within the grind. Espresso is brewed through a process in which hot water is is pressurized and forced through the coffee grounds. The resulting brew is thicker, more potent and richer than drip coffee. Servings are measured in shots, not cups and espresso is generally more potent.
Single-serve coffee stays fresh longer, remains hot and won't go stale before your reach the bottom of the cup. Coffee by the cup is simply better.
The characteristic froth or "crema" that floats to the surface of a cup of espresso is made up of vegetable oils, proteins and natural sugars; a healthier alternative to additive creamer or sugar packets.
The cutaway of the machine pictured above is an outline of the heavily tauted and publicized, Clover coffee system. The Clover was built using the same piston lever technology employed in espresso brewing, and it's based on the same push button, one cup at a time brewing system that traditional espresso brings you.
The Clover was commercially introduced as the centerpiece of upscale, in-the-know coffee shops and sold for $11,000 per unit. That was up until 2007 when Starbucks purchased the Clover system and subsequently confiscated the rights to all existing and future commercial grade Clover systems. The 250 existing non Starbucks oriented boutiques were able to keep their machines in a shared custody agreement; which allowed for maintenance, upkeep and repairs, but no new machines.
Starbucks is slowly rolling out the Clover to their new and existing stores and charging a $4+ per cup premium for coffee brewed through the machine.
Clover is currently working on a consumer model that they hope to debut in the near future.
In the mean time, high-end consumer and commercial espresso machines using the same piston lever technology that the Clover features, can be had for a fraction of the Clover's pricetag.
Also, don't forget to look into the Phillips Senseo, a pressurized single serving coffee machine that produces excellent, frothy cups of coffee. For the curious: the Senseo is not considered an espresso machine because it's patented "pods" use a paper filter and paper filters are not used in the espresso brewing process.