just installed now, looks very smooth both on 5s and SE
that will be the final version of 10.3.3 i think.
Have you tried 10.3.3 beta 6 on the SE? Now I am getting out of space errors constantly and I removed 50+ apps and turned off iPhoto sharing to free up 4gb space. Now my "other" space is over 20gb and still running out.
Guess it's time to reinstall!