While I completely agree as a self-proclaimed videophile that any type of compression means bad news for quality, YouTube comparisons still stand as valid.
1) What are you going to upload your video to? Let's face it, if you want the most views and easiest method of sharing, YouTube is going to be one of the homes for your videos.
2) While compression will degrade quality, you can still see the differences in these comparison videos. It's not like compression all of a sudden makes one upload much worse than the other. They both get compressed in the same manner. It's just that the artifacts will appear in different places. If the source video already sucks in quality, compressing it will just make that worse. If the source video quality is great, compressing it won't make it as bad as a source that was bad to begin with. Prove me wrong on this. Show me a GoPro 1 video on YouTube that looks better than a GoPro 2 video of the same resolution.
To me, it's very obvious that the ION has better image stability. The difference lies in contrast and saturation. Something tells me that even at the highest quality possible, this will still be the case between the two cameras.