Honestly, I have a love/hate relationship here. They make you strong, but you're sore for days...in a good way. I haven't done these at all this winter. Now that it is January, I'm adding a hint of intensity to my training plan. That includes this workout twice a week. I skipped a few that are just too hard to explain, but this is enough that you'll have trouble walking for a few days if you do them right.
I have a video of our speed skating team in Kansas doing these from a few years ago. Plus, who doesn't love a hardcore cover of a classic Beastie Boys song.
Edit: I forgot to mention that after each exercise you should hold a squat for 10 seconds. Do this before standing up and recovering. As soon as your complete the 10th rep, squat.