The K Duo has two (2) versions.
Both Use “Pods and Pot”, 6, 8, 10, 12oz Strong Brew feature for both, 60 oz water reservoir, KCup pods or reusable pods, and basket for ground coffee. Both have room for travel mugs and can use tea pods or hot water for tea.

"A": The K Duo has the GLASS Carafe (pot) and Hot PLate, 60oz water reserve (but not movable), and the single serve Pod feature. Larger space needed.

"B": The K Duo Plus (WHICH I HAVE) has a THERMAL Carafe, a MOVABLE 60 oz water reserve, and the single serve POD feature. Fits in tight spaces.

To me, this is a “No-Brainer”.

There are pros and cons to each of these, so it is personal preference which one to get. I have had them both. For that matter I've had 16 different KEURIG Brewers since 2006, so I have had them all. If you compare the pictures of these two, you can see why the movable water reserve on the "B" is a big plus. If you position the water behind, it can fit into a really small space like a MINI version, but still have the “Pot AND Pod” feature. The Glass Carafe with the hot plate on “A” may keep coffee hot longer, but the coffee tastes burnt after a while from being on the heat. The THERMAL Carafe keeps my coffee at a very hot temp for a couple of hours and very drinkable warm for up to 4 hrs. I can actually use my stove on warm as an added hot plate if I want to because its metal. Do you really want a pot of coffee longer than that before making a fresh one? Bring the Thermal Carafe right from brewer to table with no cords. The K DUO PLUS is by far the better and my favorite. NO KEURIG BREWER has ever been a FOREVER Brewer, they ALL have had some bugs here and there but we had to learn to keep needles clean, use good water, de-scale if necessary, especially with constant use. I've had this one for six years. I live alone in my apartment but I can have coffee with friends on the table in nano minutes and hot.That's absolutely perfect. No need for a huge Keurig brewer, especially one that only does pods. The brewer has plenty of room for a travel mug, but I use a pot to fill them. Much faster and economical.( PS...LOTS OF REVIEWS COMPLAIN ABOUT SPILL WHEN POURING FROM CARAFE. IF THE TOP IS SCREWED ON CORRECTLY, THERE IS NO SPILL WHEN POURING!!!!!)Both also have the STRONG BREW feature. Comes with basket for ground coffee and you can use a reusable pod for your own coffee or tea. Parts do wear out after time on ANY brewer. Its life. My cover to the pod housing wont stay shut all the time, but its a minor annoyance after 6 years. Some BIG huge brewers only do pods! Stupid! Takes up soo much space. Newer features like"Multi-Stream Technology" is trivial unless they want to add it to the K-Duo Plus (PSS...the new re-usable K-Cup compatiblewith the Duo Plus has the Multi Stream feature.) Adding a choice of brew temps would be good too but not necessary. Be real. Theres always something you can complain about, but the more features, the more $$$, more parts to break, and the bigger the brewer. If you want Cappachino or Lattes, theres a whole seperate unit for that. Theres not much perfecting with this one unless they do add Multi-Stream or add the brewer temp, but I can have a hot plate too I want, if keep it on VERY LOW on my stove since its made of metal. Also...GLASS Carafes BREAK I broke mine within a week. On a last note, my mom gave me a K-Mini which was in my closet. I took it out to see if I even liked it. YUCK!!! It only does pods, holds enough water for 1 cup at a time and I brewed TWO POTS on my DUO PLUS in the time it took for the Mini to brew 1 lousy..and I mean WEAK and LOUSY cup of coffee. Same amount of space. I boxed it and its going somewhere I cant see it! Absolutely NO comparison! My Duo coffee comes out faster and better tasting (I LOVE STRONG and HOT) than any coffee shop Ive been to.
Hope this info helps puts it into better perspective. I have found this one priced from $99.00 to $299.00. LOOK BEFORE BUYING!!! But buy the K-Duo Plus. You have the best of both with little space!What else do you need-someone to wait on you? Mine goes all day , eveyday!