I'm not sure why everyone says Bunn has a better mouthfeel.. I have both a Keurig and a Bunn and I don't notice much of a difference between the machines on average..
Now, some kcups and pods both stand out from others in that department, but again, on average there doesn't appear to be much difference..
as for differences (IMHO of course):
Bunn: more versatile water drops, non-proprietary, more selection, generally lower cost for pods, but also a wider range of quality in pods. If you look in front of my machines, you'll see the Bunn is messier..
Keurig: smaller selection of drop sizes, proprietary format, higher cost for kcups, but somewhat easier to use and cleaner.
I love both and I'm keeping both. I like a wider selection of pods (I drink a lot of Java One pods, but I think there are many good pods.. not good enough to be regular purchases, but good nevertheless), but I'd say my top favorites are almost all X-Bold kcups (VH Eclipse, Tully's FR, Newman's Special Blend, GM Dark Magic)
there are strengths and weakneses to both.. I'm just glad I don't have to try and choose between them..sometimes the hardest part is coming home and having to choose which machine I'm going to fire up.. and at times I just get them both awake and have a cup from each.