http://www.silvergen.com/colloidal_silver_generator.htm
As you may very well know by now, I am a huge proponent of building your own. Though if I had to purchase a generator today, I'd look for one with the most flexibility in terms of processing. Such as, with the ability to monitor both the voltage and amperage during processing.
Esstee,
If you were to buy a generator, which one would you choose?