I believe most of the gold and silver part of an overall portfolio should be safely stored above ground in a fully paid-for and unquestionably allocated manner, but gold mining stocks are a good future-orientated supplement. When people at all investment levels ultimately get interested in gold one of these days, gold stocks will be their favored venue, never mind current issues about potential theft or implosion of brokers or clearing houses, "hypothecation" of shares, etc.
For this "paper gold" of stocks, I like ASA Ltd (ASA), holding larger world class miners, and Central Fund of Canada (CEF), holding allocated gold and silver bars in Toronto. Both are PFICs* trading as closed-end funds on US exchanges, and are Bermuda and Canada companies respectively, holding off-shore assets. **
My third favorite is Global X Gold Explorers (GLDX), a US ETF holding worldwide promising gold prospecting companies. This one will eventually become the most popular play and go straight up. I think it's better than GDX and GDXJ, but it is still relatively unknown and does not yet trade in large volume. ASA and sometimes even CEF trade at a discount to the net asset value (NAV) of the fund which is great for buying quality at a discount. These discounts often disappear during very bullish gold markets.
In my opinion, ASA and GLDX are currently extremely undervalued in several ways compared to gold and silver. CEF tends to trade close to the net asset value of its stored bars, but the metals themselves are still good value after last year's pullback.
*PFICs are passive foreign investment trusts in US SEC and IRS terms. Read about the history. If one is holding PFICs through the calendar year end, there are some tax advantages to listing them each year on a US federal tax return. For shorter term trading, I wouldn't bother. Do your own research and ask your investment adviser and/or accountant, but it's not a big deal to list them on a tax return form.
**Through DRIP operator ComputerShare you can buy, and eventually sell, ASA directly without a brokerage firm and request registered shares to be sent to you. There are brokers who can do the same for CEF shares.