Some consumers that own Keurig's really love them. It's almost an obsession. I have one in my house and don't really get it. I don't like that it heats up a plastic cup to coffee hotness level. I feel like the coffee it brews is fairly weak. I tried using it with reusable cups to grind my own coffee but then it's even weaker.

However, those that like them, really like them. There are iced beverages you can make with them, or even hot apple cider. I guess this is niche, but those that will use it will get hooked.

> Can you run a Keurig with no cup to use it to just heat water?

Yes, you can. In fact, I use my Keurig this way quite often for making tea (get cup of hot water from keurig, drop tea bag in cup) and have used it to make hot chocolate and cup-o-noodles several times in the same way.