Yet another wrinkle

The whole Berkey thing has a long, sordid history with many different associations.  Originally there appears to have been Jones, Watts, and Doulton making pottery in 1815 and eventually granular carbon filters.  Watts bowed out, leaving Doulton & Co. in 1853.  It looks like Doulton predominantly used carbon.  The next step forward appears to be the Chamberland filter (also known as the Pasteur type) in 1884, which used a porcelain tube as the filter medium, but required water under pressure.  In 1891, the Berkefeld filter was developed in Germany, which established the current form of the gravity filter: an upper chamber contains raw water, which passes through a ceramic filter into the lower chamber.  The Berkefeld filter is an extension of the Chamberland filter in that it uses gravity to generate the water pressure.  The unique elements are the use of diatomaceous earth (Kieselguhr in German) as the filter media and the use of an upper and lower chamber structure.  The Berkefeld Filter Co. was separate from Doulton & Co.  In 1972, Doulton was acquired by Pearson & Son Ltd., which purchased Fairey Holdings in 1980.  In 1985 the company became Fairey Industrial Ceramics Ltd. (FICL), and acquired the rights to the Berkefeld and Sterasyl trademarks.  (It's unclear where the name "Sterasyl" came from, since Berkefeld was already using diatomaceous earth.)  FICL separated from Pearson group in 1986 and went public in 1988 as Fairey Group PLC.  Rolls Royce bought FICL from Fairey Group in 2003, spinning off the filtration division and others, which ostensibly retained the FICL name.

That much can be gleaned from Doulton USA's history of Doulton with a smattering of Wikipedia details.  However, there have been a number of companies affiliated with Doulton/Berkey, and their relationship isn't always clear.

• Royal Doulton is what remains of the original parent company after the 1972 buyout by Pearson Group.  Along the way they were bought by Waterford Wedgwood, which went into receivership in 2009.
• Fairey Industrial Ceramics Ltd. owns the trademarks Doulton, used independently of Royal Doulton, and British Berkefeld, though not "Berkey".  They still manufacture the Doulton "candle" filter elements, Sterasyl, etc., and license some trademarks to New Millennium Concepts Ltd. in North America.
• New Millennium Concepts Ltd. owns the trademark to the Berkey name and expanded the lineup of gravity filter systems to several sizes.  (According to one site, the stainless steel systems are manufactured in India.)  They also produce the Black Berkey filter elements, which have an unknown pedigree.  The claims made by NMCL exceed the claims of FICL with regard to capability of the Super Sterasyl filters.  For example, only the Super Sterasyl ATC media is rated for lead removal, but NMCL claims that the Black Berkey elements are comparable.  NMCL has been the British Berkefeld master distributor in North America since 1998.
• Doulton USA sells the Doulton candles, but worth noting is that they aren't related to FICL or Royal Doulton either!  The bottom of their website notes that Doulton USA is a unit of Eco Systems International LLC, which also sells AquaCera filters.
• Ceramic Filters Company Inc. manufactures AquaCera filters, which are often sold as lower-cost substitutes for Doulton filters.  According to their website, they were the agent, importer, and distributor for Doulton and British Berkefeld in 1989.  Apparently NMCL won the master distributor rights, but apparently CFC still sells the Doulton systems.

That's a long, sordid history with lots of players.  It's not surprising that people get confused about what is what in the world of Berkefeld.

For anyone reading this, after my personal experience with NMCL, my suggestion would be to make your own filter unit out of two food-grade buckets and use the Doulton elements.  While I have yet to get any to test, those have the most history behind them.  We know relatively little about the Black Berkey elements, and while they do improve water taste, they have an alarming rate of failure (3 of 4 elements that I have failed), for which NMCL didn't issue a recall, and there are shady business practices with regard to claims of laboratory testing (source).  Should comparable performance be required, get the Super Sterasyl ATC candles, which supposedly handle lead and organics.  St. Paul Mercantile has an excellent FAQ on the Doulton filters, including a link on how to build one's own bucket filter.

I think that for my SHTF water filter, I may have to go with a Sawyer.  And I may get a Katadyn Pocket just for good measure.

Edit [2012.02.03]: Except that I've read that some viruses get down to 0.004 micron, so the Sawyer may not be sufficient....  Also, the "candle" terminology comes from the French "bougie", used in other medical contexts.  Lastly, gravityfilter.com is pretty cheap.