We have seen an internal build of the Android 5.0 Lollipop running on the Samsung Galaxy S5, courtesy SamMobile. Now they have managed to get their hands on an internal Lollipop build for the older Galaxy S4, and have a video for us to see below.
In terms of design, the Lollipop build of the Galaxy S4 is pretty much identical to that on the S5. You have the new notifications that appear on the lockscreen and everywhere else in the UI. The stock apps have been updated with new Material Design UI elements. The multitasking menu also has the new card-style layout.
In terms of performance, the build was said to be much faster than KitKat and better at managing memory. SamMobile haven't released the build because it's not exactly stable but you can watch check it out in the video above.