My employer offers AFLAC and, as the HR Director, I have looked closely at their policies. Frankly, many of the policies just don't seem worth the money. That said, I did purchase their cancer, whole life, and term life insurance policies and I am glad that I have them.
Eight months after purchasing the cancer policy, I was diagnosed with basel cell carcinoma, a common skin cancer that is not life threatening. It was removed via Moh's surgery. AFLAC promptly paid me $800. I was impressed with the ease of filing a claim and the speed of payment. As someone fair skinned with a history of wicked sunburns, I doubt that was my last experience with skin cancer.
I recommend looking closely at their policies and comparing the AFLAC benefits to the group benefits that your employer already offers. Take into consideration how much you will spend per year on the policy vs. any benefits derived from it. AFLAC also offers a variety of riders on their policies, such as premium refund in the event of no claims after so many years and increases in benefit maximums to keep pace with inflation. Not all reps will promote the riders, so ask.