I have to agree that Sovereign Silver would be a much better choice than NOW. For future reference though, Sovereign Silver has a very large presence in retail supplement outlets thanks to a succesful marketing program, but it is pretty much in the mediocre range of commercial products when it comes to the vital measurement of total surface area.
While their product measured to have about nine times the total surface area as home-made silver with the SG-7 home generator unit (0.217 centimeters per milliliter of solution versus 0.024), they had less than half the surface area of ASAP 22 for example and less than 1/4 the surface area of Source Naturals, about 1/7th the surface area of Kelly Colloidal Silver, about 1/150th the surface area of Utopia Silver and even less still than Mesosilver.
Which is not to say that Sovereign Silver will not work or get the job done, just that there are significantly better alternatives out there at a comparable or lesser price. For comparison's sake:
Sovereign Silver retails for around $12-15 per ounce bottle and sells on the net for around $8-10 plus shipping. ASAP sells for around $25 to $30 plus shipping per 8 ounce bottle on the net (and retails for more), Kelly Colloidal Silver is only $15 plus shipping per 8 ounce bottle on the net, Utopia Silver and Mesosilver sell for around $24-$25 (less the 15% discount for CZ members for Utopia Silver) plus shipping for an 8 ounce bottle. Source Naturals is a bit pricey ($60 plus at most outlets), but that is often the case for their products.
Three products that have very small surface areas that I would be leary of are: Oxysilver, Silver Shield and Silver Biotics. Oxysilver has almost no silver surface area at all (it tested at 0.0001 centimeter per liter!), and the Silver Shield and Silver Biotic products have little more surface area than home-made silver solutions (so why pay retail prices for something you can equal at home for pennies?)