Bitcoin, absolutely. Bitcoin will be the next payment system and will rise much more. Gold as payment system is old school idea but its important for industry.
If you want to choose bitcoin over gold, there are a lot of reasons to do that but what kind of a reason is that it will be the next payment system? Gold stopped being a payment system years ago. If you want to compare bitcoin and gold, you should compare it by comparing its qualities as a currency. Qualities like medium of exchange, unit of account, portability, durability, divisibility, fungibility, store of value point out that bitcoin is much more advanced than gold.
That's true, bitcoin is much more advanced than gold, but I still have faith in gold that it would survive for many years, on the other hand bitcoin is unpredictable as there would many other digital currencies in the future which can replace bitcoins.
The only thing I like about bitcoins over the gold is the amount that you can carry with you in your digital wallet is unknown to anyone. Whereas you cannot carry a large amount of gold across the countries, or else customs can put you in trouble.