On my Lumia 920 and 735, build 10080 is extremely slow most of the time when it is supposed to show the start screen with all the tiles. Whether it comes from a locked screen/standby or returning from an app.
It is too slow to be useful (more than 6-10 seconds delay in many cases, sometimes even more), so I had to revert back to WP8.1.
Anyone else having this slow start screen opening issue?