Watching the archive (which is not a direct quality comparison as it's more like a high setting recording) and the stream looks rather good, the sound stuttering seems to be from major and most likely the twitch streaming app choking or glitching.
It would be nice if there was a way to cap bandwidth upload rates or maybe drop res a bit, I can upload at twitch's max rate of 2.6 but if I do so in the middle of the day my ISP (virgin media) will limit my upload down to about 0.8 and cause a lot of problems, the way around that is to stream at about 1.2 so i'm not going above a 900mb per hour limit.
Small things like that are kind of needed as settings, a lot of UK people are going to run into that limit as virgin media internet is popular for a lot of people.