BMO on silver below. I read that one of the differences with SLW and other royalty related companies is that SLW gets paid its royalty in actual silver versus dollars of some kind.

Event: BMO Research increased short to mid-term silver and gold price forecasts
Impact: Positive. BMO Research has increased its target price for Silver Wheaton to US$46 given the solid growth track record and increasing cash flow. The stock has been upgraded to Outperform reflecting the increased NPV and earnings resulting from higher forecast silver and gold prices. Forecasts: The company has provided 2010 attributable production guidance of 22.0Moz silver and 28,000oz gold (23.5Moz silver eq.). By 2013, Silver Wheaton anticipates attributable production to increase to ~40Moz silver equivalent, driven by the ramp-up of Peñasquito and Pascua-Lama.
Valuation: Silver Wheaton is trading at 1.9x its 10% NPV at spot prices. The revised target price of US$46 represents 2.5x its 10% NPV using spot.
Recommendation: Silver Wheaton is upgraded to Outperform following an increase in BMO Research’s short to mid-term silver and gold price forecasts. The company offers a compelling business model that continues to generate significant free cash flow at current silver prices and has the financial flexibility to pursue strategic silver stream acquisitions.