After working out with KBs for upwards of a year in the last year and a half, I'd say the biggest drawbacks to using them is unquestionably...
...the blisters.
Thought developing callouses would help, and they did for a while, but they definitely make the workouts unplesant and that's extremely de-motivating.
The 40, 50, 60+ minute workouts I'd like to do are not possible with KBs heavier than my 20 pounder. My hands would be covered with blisters within 30 minutes.
So, I'm going to experiment with a solution.
*Sigh* Yeah, you'll be laughed at if you wear these in a gym, but I workout at home, and the more blisters & callouses I've had the more I realize I like palms soft.
Will report back if they're worth the money and if they're effective.