Frigidaire 1-Cup Single Serve Retro Coffee Maker: This machine from Frigidaire was a speedy and did the job. It has no frills and is the cheapest option on the list at just $38. It does feel and look a bit cheaper than the others on this list, but will brew a cup of coffee in under 2 minutes.
Proctor Silex Single Serve Coffee Maker: Proctor Silex's entry on this list is in the same tier as the above Frigidaire. It's a bit slower than that one, but provides a similar bargain price.
Hamilton Beach FlexBrew Single-Serve Coffee Maker: The Hamilton Beach single-serve option is still quite affordable, just $60, but adds an additional feature: regular and robust settings. In our testing, the robust setting did have a modest but real increase in the strength of the coffee.
Hamilton Beach FlexBrew Dual Coffee Maker: This coffee maker is essentially the above Hamilton Beach attached to a drip machine. The single serve portion did not perform noticeably differently from its standalone counterpart. It's a bit cheaper than the Keurig K-Duo listed above, but the K-Duo feels more solidly made and brewed coffee a bit better.
Cuisinart Coffee Center 2-in-1 coffee maker: The Cuisinart 2-in-1 Coffee Center brews both single servings and carafes with both bold and regular options. It has additional features -- like the option to keep a carafe of coffee warmed to different temperatures -- but none that made it comparable to the K-Duo in my estimation, which felt more solidly constructed and brewed better in our tests.
Keurig K-Supreme: The K-Supreme, like the other Keurig machines on the list, performed a bit better than other brands. It's a smaller option with a detachable reservoir. It has four size options and settings for strong coffee and brewing over ice. If you want a couple more options than the K-Mini, but don't want to inundate yourself, it's a good choice.
Ninja Dual Brew Pro: This Ninja coffee maker can do it all and was a close contender with the K-Cafe Smart for best for customizing. It can froth milk brew carafes and coffee pods and even has a separate dispenser for hot water, all with a smaller footprint than the K-Cafe Smart. To my taste and our tests it didn't brew quite as well as the K-Cafe Smart, but at $180, is relatively cheap comparatively.