I've been using kettlebells for weight loss since the start of this year. They really can give you a full body workout and have the ability to burn a lot of calories in a short amount of time. I really like the stack 52 kettlebell exercise cards that you can find on Amazon. You can easily shuffle them for a random workout each time.
For me personally, I started out slow. 20 minutes a day, 3 days a week. This was using a 10 lb. kettlebell. Over the course of the last several months, I've slowly moved up to using a 25 lb. kettlebell. I try to make it a point to get a 20-minute session in each day Monday-Friday, resting on the weekends. Combined with a not-so-strict Paleo diet and I've been very happy with the results.
I've lost over 50 pounds with 20 pounds left to go in my goal. You'd be surprised at how motivated a fall wedding date can make a person! In fact, my fiancee, is doing the same routines and workout schedule I am and she has had amazing results as well. I can't say enough good things about kettlebells.