The GX is smaller on the 4Runner chassis, the LX (cruiser) larger and more trucklike.
The GX is sportier, the LX is more truck like and built to a tougher spec.
The Lexus versions of both have a superior interior build.
The GX is dimensioned better for trails, IMO.
Aftermarket is better on the Cruiser.
I've only driven the newer ones, but IMO interior quality goes:. Cruiser, GX460, LX570.
If I could only own one, it'd be the land cruiser for overall build and flexibility.
GX would be better as a daily driver.
Parts are cheaper on the GX