Tonight, at first I couldn't get it to record any point or even show any speed, even though it had a lock on 8 satellites. But after the third or fourth try it faithfully recorded three trips between 2-10 miles each without skipping a beat, all with the phone in standby. Strange.
I did notice though that when you set the GPSLogger option to keep the backlight always on, and then put the phone in standby, the screen will dim right away (as expected) but eventually the phone gets kicked out of standby. Makes sense in a way, I guess, since this puts the phone into two competing and conflicting modes.