I've had trouble with the backlight also -- seems to be something that was "fixed" in various versions of the firmware. What I really like to have is the backlight to stay on while there is activity. The radio seemed not to do this very well. There also were time when the light would come on and stay on for no known reason. Other times, it would flash on and then go off even while a user was talking.
I've been playing with various versions of the FW and I am currently running 1.02.03. So far in this version I've been able to get the radio to do what it is supposed to do when I set all settings to 10 seconds. I think it's time to go back and try "while a user is talking" (open squelch?) again.
On a somewhat related note (ok, maybe not), there seems to be a related issue with recording. In fact, recording seems to cut off about a 1/2 second before the user stops talking.