I have the XT10 along with a few other Klarus lights. I have a new found obsession with their new interface, the XT line really hit my wallet in the past two weeks.
The XT line is aimed at the Tactical market/user. After being power off, it always turns back on in High mode (default) since the light does not have a memory. When off, mode button is instant access to strobe.
+1 on Going Gears videos, very good information source.
ANSI from what I understand is a standard for measuring flashlight output...