Both of these have their own challenges, since the shutter needs to stay open longer more light will be let into the camera causing an overexposed picture if settings aren't set correctly. The other challenge is getting the focus as good as you can while moving blind with the moving subject. Since the shutter will stay open while you are panning with the subject you aren't able to see through the view finder. There can be a lot of hit and miss, if you only have one shot to get it right it can be trash, but if you have my subject you can just ask them to keep running back and forth until they are too tired. My husband was thankful I only asked him to do this a few times, but my daughter thoroughly enjoyed it.
I do want to try this again with a longer shutter speed and different subject. I would like to get the art of panning down, so when I come across another wonderful or just perfect moment to capture movement and make it a blur, I have the knowledge and tools already under my belt to do so. But not bad at all for my first attempts at doing this.