Thanks for posting the videos, none of the Spotify links work for me in Malaysia, apparently the third world doesn't deserve culture! >: (
I'm not into classical music apart from the occasional piece and therefore have no idea how I would even begin to compare two performance of the same piece since they always seem to be so
perfect (I always assume all of these musicians have started rigorous training since kindergarten and there is NO room for error or improv of any kind!).
But thanks for your thoughts and effort, it helps to bring this elusive topic to laymen such as myself. I will be following occasionally.
Edit: Actually I found a few Juliard quartets so I'll give them a go since you say they're among the best!