You are seeing Kettlebells everywhere currently because you have some aggressive marketing campaign attached to them. That does not make them a “bad” strength training tool. It only makes them a “hyped” strength training tool. Personally, I think Kettlebells can build strength every bit as well as Dumbbells!
Are they worth the money? That question is “loaded.” Is eating out at an expensive restaurant worth the money? You can buy the same food at the grocery store, go home and prepare it and have the same end result nutrionally. I think the answer is, they are both great options. If you can afford to eat at the expensive restaurant go for it!
I look at Kettlebells the same way. You can use a Dumbbell and perform every movement that you can with a Kettlebell. Do you need a Kettlebell? No, but if you have extra money that is burning a hole in your pocket, why not? Otherwise, Dumbbells will work just as well.
In fact, Kettlbells are not as efficient as Barbells and Dumbbells for getting the job done. What I mean by this is that there is a reason that Barbells and Dumbbells became the strength training tools of choice many years ago. They are more practical, in that you can add or remove weight based upon your own strength level. You don?t have to continue to purchase a new Dumbbell every time you gain in strength, as you do a Kettlebell. This is good for you (the consumer), not to good for the Kettlebell marketing machine.
Those who tell you that Kettlebells have a different feel than a Dumbbell are correct. They certainly have a different balance to them. Does that make them better? No, it makes them different. After a period of time you will adjust to the “different” balance and then what? In fact, every item that you pick up has a “different” balance to it.
If you want to work with something that is “off balance” or awkward, you can simply add five or so, more pounds to one end of your Dumbbell. That would make it a bit more difficult to lift, for a while, until your body adjusted to it. At that point you could either add, or remove more weight to make it even more “off balance.” Gee, do you think I could start a fad with this sort of training? I could send flyers out to all of the homes: “New revolutionary off balance Dumbbell training.” I could even have tournaments and give seminars. No, that wouldn’t work because most lifters already own a pair of Dumbbells, no sale there, (sigh).
Back to the issue: Every item under the sun has a different balance to it. If you live in the country go out back and find a heavy rock. Now perform bent over rows with it, big difference from a Barbell huh? Does that make it “better” than a Barbell, or just different? The reason that there are no rock lifting organizations, and it is not heavily promoted, is that no one can make enough money doing it. Heavy rocks are free and plentiful, if you know where to look. (Not such an unrealistically cynical view if look long and hard at the matter).
However, I think it?s great to perform movements with various strength training tools. That?s one reason that I do Strongman training in addition to Barbell/Dumbbell work and free weight exercises as well. And yes, I own a pair of Kettlbells. I had some extra money a couple years back and decided to see what the big deal was all about. They are fun to use because they were different, like that heavy rock. However you only have so much training time. How much time do you think should be devoted to Kettlebell training? I also own a Leg Press machine, but almost always do Barbell Squats, as they are the superior movement.
Why do I then own a Leg Press machine? I think one reason is variety. When you train over a long period of time it is nice to have some variety available to you. Is it necessary? No, it?s a luxury, sort of like that fancy meal I mentioned earlier. Same with Kettlebells.
To specifically answer your question: No Kettlebells do not “work better than Dumbbells.” They are both tools, which can help you achieve your goals. No, you don?t “need” to add them to your arsenal of strength tools, unless you have the disposable income and are looking for a way to spend it. Otherwise, march on with the single best strength building tools that are available: Barbells and Dumbbells! If you get bored, go out back and find that free heavy rock!