Does gold window film reflects more or less light and heat than silver?
Each manufacturer publishes ratings for their products. You’ll want to compare:


Visible light reflected
Visible light transmitted (that’s transmitted from exterior to interior) 
Total solar energy rejected (this will be a %)
Solar heat gain coefficient
U value
Solar heat rejected (this will be a %)


Comparing these ratings will tell you their performance, and thus which is “better”.

Also, you can get a rating of visible light to solar heat gain. It’s a ratio you may want to consider. One type of film may block a significant amount of solar gain, but will make your room “dark”.