According to my views the marketcap of both of these will be the best tools to find out that how much people are holding bitcoins and how much people are holding gold. With that we can calculate all the things in a summarized form.
Total gold market cap = $7,617,683,440,065 (physical gold only)
Total bitcoin market cap = $14,460,218,610 (Value of all bitcoin created)
bitcoin market cap = 0.189% of gold's
Total gold market cap = $22,000,000,000,000 (actual gold traded inc. paper gold)
Total bitcoin market cap = $14,460,218,610 (Value of all bitcoin created (traded volume unknown but significantly less)
bitcoin market cap = 0.066% of gold's
I think holding bitcoins is for me better because its more profitable on a short term and with gold you really need to have patience.