The gist: This machine is clearly a fan favorite, as it’s raked in over 2,400 reviews on Amazon, giving it an average of 4 out of 5 stars — with over 60% of users awarding it a perfect 5 star rating. The machine comes with a lot of bragging rights. Not only is it “Amazon’s Choice” for super-automatic espresso machines, it’s also their #1 best seller. 
The first machine for making espresso was built and patented by Angelo Moriondo of Turin, Italy, who demonstrated a working example at the Turin General Exposition of 1884. He was granted patent no. 33/256 dated 16 May 1884 (according to the "Bollettino delle privative industriali del Regno d'Italia", 2nd Series, Volume 15, Year 1884, pages 635 – 655). A certificate of industrial title was awarded to Mr. Moriondo Angelo, of Turin, for an invention called "New steam machinery for the economic and instantaneous confection of coffee beverage, method 'A. Moriondo', Plate CXL".
The Mr. Coffee Optimal Brew coffee maker System has a highly modular design, with its rectangular water reservoir easily sliding in and out of the chassis. For those who only want a cup of basic coffee, you will find that the Mr. Coffee Optimal Brew coffee maker System will do that very well – its "brew now" button is found on the front of the machine.
The very first espresso machines worked on a steam-pressure basis, and they’re still in use today. With this type of machine, steam or steam pressure is used to force water through the coffee grounds and produce espresso. Some steam-driven machines can produce a measure of foam “crema.” But they can’t generate enough pressure or provide the precise temperature control necessary to produce true espresso: They simply make a very strong cup of coffee. However, they cost considerably less than pump-driven machines. Our verdict is that if you’re a true espresso lover and seeking to make a good shot at home, we recommend you steer clear of steam-driven machines. They’ll likely disappoint you.
Our brew-performance tests measure the brew temperature and contact time (how long water stays within a sweet spot of 195° to 205° F for brewing). We measure concentration using a refractometer, a device that measures the amount of coffee dissolved in each brew. Our convenience tests look at how easy it is to set timers, fill the reservoir, clean the machine, and more. And for the first time, we’re incorporating predicted reliability and owner satisfaction ratings into the new Overall Score for each model. We determine these ratings for each drip coffee maker brand using survey data collected from thousands of CR members.