I did the kettlebell series on the app. Agree with Sam that the one off kettlebell workouts are overall better. I liked the arms days of the series best. All the days are three circuits like Rev, which is great if you like the exercises but not if it's a dread loop you're stuck in. And there's a little bit of abs every day, which I wish she'd do all the time tbh.
The legs days seemed to be overreliant on moves you could just do with dumbbells e.g. lots of lunge variations. The swings were the only kettlebell-specific thing on those days IIRC.
Whereas with upper days you have kettlebell press, kettlebell cleans and the uneven push ups which are tricky on a kettlebell. The full body day had windmills and I think snatches or cleans and was tough and interesting.
Thanks for the inspo- I think I'll repeat one of the arms and full body, and perhaps use Heather Robertson for legs this week. Need a break from the barbell.