Other one cup coffee makers focus on a broader range of coffee beverages.
As mentioned elsewhere, the only “open format” for one cup coffee makers is the coffee pod.
Any coffee company can make coffee pods and sell them for use in pod brewers.
Then there is Keurig’s approach to single serve coffee with their proprietary K-Cups. K-Cups are not an open format. You need permission and a license to put your coffee in a K-Cup.
But Keurig does grant licenses, and more and more coffee companies now offer their coffees in the K-Cup format.
This latter “closed format” scenario is also true of Tassimo’s T-Discs, Flavia’s filter packs and the Nescafe Dolce Gusto’s smart capsules.
All of these machines pre-package coffee and coffee beverages in their own proprietary discs, packs and capsules.
Their focus isn’t just on making coffee. While pod brewers and even the Keurig machines maintain a strong focus on brewing one cup of gourmet coffee at a time, the Tassimo, Flavia and Nescafe Dolce Gusto 
Do you want to make a cappuccino with a milk product that has been packed in a capsule? That’s up to you. But it strikes us that each of these beverage machines has moved one step closer to convenience and one step away from the gourmet coffee experience.
If you love gourmet coffee, and making gourmet coffee, stick with the Keurig K-Cup brewers and the coffee pod brewers.
If you love the idea of being able to make a wider range of coffee shop coffee beverages, all with the one machines, and all without ever having to handle anything but capsules and discs etc, go for one of these machines.
They are certainly convenient, and many people rave about the quality of the drinks they serve.
Review of other one cup coffee makers:
The Dolce Gusto One Cup Coffee Maker
The Dolce Gusto Circolo Single Serve Coffee Maker
Bosch Tassimo Hot Beverage System
