I was lucky enough to be invited to see the SAE oil filter tests about a year ago and here is what I witnessed:
1. Fram (regular) - 97% double pass efficiency
2. Mobil 1 - 99% double pass efficiency
3. K&N - 98% double pass efficiency
4. Motorcraft - 98% double pass efficiency
5. PureOne (Premium) - 96% double pass efficiency
6. STP - 97% double pass efficiency
7. Fram ToughGuard - 97% double pass efficiency
8. Wix Premium - 98% double pass efficiency
There were a few more, but those were the only ones I took notes on, as they're the only ones I generally use. Many of these filters did much better on the single pass test, infact many had the same percentages as the mobil 1, however as we know oil passes through a filter more than once so I generally just blow off those tests. Here is another site with some good info on it...
http://people.msoe.edu/~yoderw/oilfilterstudy/oilfilterstudy.html