There are four types of espresso machines: manual, semi-automatics, super-automatics and built-in espresso machines.
Espresso purists tend to prefer manual espresso machines, also known as piston or lever espresso machines, but using them does take some skill. After evenly tamping the coffee grounds into the filter, the user pulls down on a handle to force the water through the coffee. When you pull the handle, as well as how fast or slow you pull it, affects the taste, and the physical effort can be tough for some people. Given the learning curve, homeowners often opt for a semi- or fully automatic version.
With a semi-automatic espresso machine, you fill the porta filter with ground coffee, but instead of using your arm power, the machine uses pump to create the pressure. A pump is very consistent in its delivery, so even if there are slight variations when it's brewing, it will make a taste of the coffee different. Most of the semi-automatics have a frothing feature on the side, so you can froth or steam your own milk, mix it with espresso shot and make cappuccino or latte. These machines have a tank in the back and need to be filled up with water. The only downside of this type of machine is that it doesn't store your coffee grounds. For every cup of coffee you have to fill the porta filter with ground coffee.
Super-automatic espresso machines allow you to store coffee directly in the unit as well as grind it freshly each time you use it. Super-automatic machines tend to be bigger than semi-automatics, so make sure that you have enough space in your kitchen. They are designed for speed, convenience and less mess or maintenance. Super-automatics will grind a pre-measured dose of espresso beans and extract a specific amount of coffee, from demitasse espresso to full cup of coffee. The used coffee grounds are placed into an internal bin that you need to dispose once it's full.
These large (and expensive) machines have displays that tell you what you are doing or what you need to do. For example, it can tell you when water tank is empty, when you need to empty the coffee ground bin, when to clean and decalcify the machine, etc. All super-automatics have a frothing feature if you want to make your own cappuccino or latte. You can also get an instant hot water for your tea or soup. Some super-automatics have an automatic frothing feature which lets you mix coffee and milk at the same time with the push of a button. Built-in espresso machines are pretty much the same as super-automatics, except that they need to be built into a kitchen cabinet.
When it comes to cleaning, most models are self-cleaning. Every couple of months you need to use the cleaning solution that will clean your machine internally.