New York Times has an article written yesterday - Coke Is Holding Off on Sipping Facebook’s Beacon that's considered the best overall coverage of Facebook's Beacon, so far.  One reader, who commented, noticed Facebook's stated policy on Opt-Out actually wasn't working:

"…Yesterday, Friday, when a Beacon alert came up after playing a game on Kongregate.com, I returned to Facebook and the checkbox next to "Always publish stories sent to my profile from this site" was unchecked, so it had to be selected.

Toady, Saturday, when a Beacon alert came up after buying movie tickets on Fandango, that checkbox was already checked. Is this a change of heart for Facebook? Are they randomizing it? Is it different per publisher?

Many advertisers are taking a pause on Facebook Beacon as well:

"..I’m hardly the only one who found a gap between what Facebook said and what it did. And this may be costing it some of the blue-chip support that it had amassed. Coca-Cola, for example, has decided not to use Beacon for now.

“We have adopted a bit of a ‘wait and see’ as far as what we are going to do with Beacon because we are not sure how consumers are going to respond,” said Carol Kruse, Coke’s vice president of global interactive marketing, this morning. Coke had been one of Facebook’s “Landmark Partners” because it had made an especially large commitment to use the site’s new features. Other Landmark Partners included Blockbuster and Verizon. "