One is gold, the other complicated (each additional function of a watch is called a "complication" - this one has a perpetual calendar as well as the chronograph). Both will retain value and may well appreciate - we have seen significant increases in both gold and the value of vintage Heuers in the last 10 years.

It really comes down to your partner's preferences - does he like more buttons to press, or classical gold? A dressy watch, or one in everyday steel?