UI is great and easy to navigate.
Love that the voted up skins show right up in your favorites for easy access.
AK didn't come up for me as an option. Had one in inventory and on hot bar. My M249, L96, Ice pick, and LR all did though.
Workshop skins take a bit to apply. I tried switching weapons around and nothing instant but after a couple minutes it showed up. I'm guessing just an effect of the massive amount of skins available.
Overall I love it and look forward to being able to change my styles up.