According to Consumer Reports:

Carafes are all about compromises. All were so-so for removing off-tastes. Though the Pur was the best at removing contaminants, it clogged well before its claimed life of 40 gallons, so you'll be replacing filters more frequently. The Brita and the Shaklee didn't clog, but the Brita wasn't very good at removing lead. The Shaklee fell down at removing chloroform.

On sink-mounted units: The faucet-mounted Pur does what a filter should do and doesn't take up any counter space or have any unsightly visible tubing. But it clogged quicker than its claimed life span. The countertop-type Kenmore (Sears) 34551 filters water faster, doesn't clog as quickly, and costs less to operate than the Pur. The undersink Kenmore (Sears) 38454, though not as good at removing lead, combines excellent overall performance with an unobtrusive appearance. Its operating costs are low but it should be professionally installed, which adds about $150 to $300.

Hope that helps. We have a Brita carafe, and have had no problems with it. Lead isn't a problem here.