Inferior to basically any other method of brewing coffee. Even among pod systems, for instance, it's markedly inferior in quality and environmental impact to, say, Nespresso, which uses all-aluminum pods which are fully recyclable (Nespresso even composts the coffee inside the pods).
Nothing's wrong with the biodegradable pods, although those aren't going to be ideal for quality either, and those are a tiny slice of the market.
The simple fact is that this is an awful product that is doing vast amounts of environmental damage. Read up a bit yourself and you will see what I mean.
I have a Keurig at home, and I exclusively use the reusable metal mesh filters you can find right next to the machines themselves at the supermarket. The only thing that gets "thrown out" when using those are old coffee grounds, and I don't throw those away, they get added to my garden soil for extra nutrients[1].
I realize that I'm probably in the minority among Keurig owners, and I certainly wish the company itself would be more responsible and make 100% recyclable pods. The way I see it though, the machines themselves are nearly loss-leaders; Green Mountain (parent company of Keurig) makes almost all of its money on the throwaway pods, and they aren't getting a dime out of me.
Instant hot. You can buy a instant hot water dispenser for your sink, and decades ago they were really cool and lasted for a decade, but the modern ones are all precision engineered for maximum profit to fail in less than a year, requiring plumbing work to replace. There are desktop hot water dispenser products but they cost about as much as a loss leader k-cup machine.
Also my wife has one of those re-usable coffee grounds things but sometimes you just want a quick cup and don't want to fool around. Today I'm running late and if I had an extra 5 minutes I'd stop at starbucks and blow $5 instead of 0.50 on this disposable cup or $0.005 on home ground. I drink black tea and I have an emergency stash of tea kcups. I think it slightly inferior but not that bad. It is much more bitter than my looseleaf home brewed. Obviously my kcup tea always tastes kinda coffee-ish which is a little gross.
I only drink one cup of coffee a day at most and my wife hates coffee, so rather than brewing even a small 4-cup pot, I'd rather not waste anything and just do the one cup at a time that my Keurig offers.
In other words, not only am I being environmentally responsible by not using throwaway pods, I'm also not wasting a bunch of coffee and paper filters using a traditional drip machine just to get my one cup every morning.
It's so inferior and awful that it represents a quarter of the market in the U.S. and growing. The convenience and pretty good taste for non coffee snobs makes for a successful product.
Nothing's wrong with the biodegradable pods, although those aren't going to be ideal for quality either, and those are a tiny slice of the market.
The simple fact is that this is an awful product that is doing vast amounts of environmental damage. Read up a bit yourself and you will see what I mean.
http://en.wikipedia.org/wiki/Environmental_impact_of_K-Cups