There are some differences between the L920 and L925.
The L925 is lighter with 139g vs 185g of the L920.
Also the L925 is more slim with 8.5mm vs 10.7 of the L920
The L925 screen is AMOLED, richer colors, deep contrast and great view angle but the colors are not accurate for some. The L920 is IPS LCD and is more accurate in color range but not that vivid as the L925 AMOLED.
Most L925 only comes with 16GB of internal storage vs the 32GB of the L920.
Most of the people that bought the L925 is because the slimmer and lighter body of that phone, for some the L920 is heavy and bulky.