Is it advantageous to own precious metals directly, versus the stock of companies in the precious metals business?

Direct ownership is problematic for many reasons. Safe storage of the asset is the first one tha comes to mind. You either do it yourself or pay a fairly steep fee to have the seller store your assets. If you take delivery, the sale process is not easy if you are not very careful. Establishing an accurate price for the asset should you decide to sell is also difficult if you take delivery of the asset.

In addition to owning shares of companies in the business, you should investigate the Exchange Traded Funds markets as several of the precious metals ETF's will allow you to take delivery of the "underlying" or "physical" if your holdings are large enough. They also tend to trade more in line with the price of the underlying asset than do the miners and processors stocks.

Hope this helps.