They are both easy to use, and come in various flavors and styles of coffee. That's where the similarities end between K-cups and coffee pods. Coffee pods are very simple little doses of coffee grounds, in a flat little round pack that looks a lot like a teabag. No bells and no whistles. They can be used by several different types of coffee machine, such as the Senseo, and pod-based models of Melitta, HomeCafe, Bunn, Krups, and Cuisinart. And not only are they flexible enough to use in several types of coffee maker, there are several companies that manufacture the pods. This gives you a good selection to choose from without being limited by one particular line of coffee. Of course, Senseo makes their own pods but you can also get pods from Miss Ellie, Java One, Wolfgang Puck and others. Between them, you can get nearly any possible kind of coffee in pod-form. Kona, Jamaican, Colombian blends for those who prefer the natural varietals, or get some French Vanilla or even a simple decaf. Senseo offers some pods for making tea as well. Now, a look at the K-cups. Clearly, they are designed solely for use with the Keurig line of coffee makers, so are a bit less flexible in that regard. But they have put together an impressive line of varieties that it really doesn't make that much difference.
Most of the K-cups are made with Timothy's coffee, but there are also selections from Gloria Jean, Green Mountain, Wolfgang Puck, Emeril and the Coffee People. Again, more coffee choices than can be listed. There are K-cups with varietals, decaf, and flavored coffees in many different types of roasts. Their tea selection is very diverse, including teas from Bigelows and Celestial Seasonings. One thing that K-cups have that pods do not have, is hot chocolate. While the pods are simple gauze pads, the K-cup is a more complicated little package. They are made with hard plastic, and the filter is sealed inside with the grounds. The little container is part of the brewing system, and helps to produce the right amount of pressure and water flow for brewing. Is one kind of single-brew system better than the other? It's hard to say.
The K-cups are more expensive than pods, and take up more space because of their plastic shells. But you also get more choices, and the Keurig machine will make hot chocolate which you can't do in a pod machine.