Hi.
I’ve been trying to learn the USX motion and trying to play these basic pentatonic runs. The USX motion feels pretty weird and when increasing speed my playing becomes sloppy and the accuracy starts to suffer.
Sometimes after hours of concentrating I’m able to get it to work decently but I feel there’s something I might be missing or doing wrong? I would really appreciate feedback on my technique.
Link to the video.
IMO, it looks pretty solid and kinda reminds me of my picking, except I feel like my thumb / index moves a bit more. Personally, I feel like 2 notes per string is pretty hard to get up to speed, so maybe try to go all out on one string first, then progress from there.
Welcome @cristian! Thanks for posting and good job on the filming!
I agree with @Pepepicks66 that this sounds pretty good!
One obvious thing is that your slow and fast movements are very different. The fast motion in particular is very flat: not all the upstrokes escape fully, so you can see in the slow motion clips that you occasionally “swipe” and hit an unwanted string on your way to the new string. Could this be the source of the discomfort you are feeling?
So one thing you can try is to make the motion slightly more diagonal so that the upstrokes escape a bit more. Just as an experiment you could try something like the “Gipsy form”, where the wrist is flexed and the motion can be a mix of wrist and forearm - which tends to create a more pronounced USX trajectory:
Out of curiosity, have you also tried these licks with DSX starting on an upstroke? How does that feel?
I agree with the previous comments; I think the sound and picking looks good for the most part! 
Like @tommo pointed out, your picking motion is a bit irregular and some of your pickstrokes escape more than others. This causes unnecessary swipes at times, at least on the ascending side – you can see it on the 5th note of each pattern on the two first repetitions in the slow down part of your video. Maybe that is part of the feeling of inaccuracy or sloppiness?
Here’s another thing you could try which I posted on another topic: