Summize has always been fast and reliable. In fact in the days of the worst Twitter outage, with Reply and other functions disabled, Summize was the savior of the Twitterverse. But now that Twitter acquired Summize, I’m seeing it dead quire frequently.
The Twitterization of Summize has begun
Update (7/24): In the meantine Twitter closed the deal with Summize, it’s now rebranded as Twitter Search. While Summize used to be rock-solid and fast, I can confirm that Twitter Search is spotty (simply missed entries) and is often delayed. A sad transition, indeed.
Update: (5/22/09): Finally, a year later others agree that Twitter’s Search Engine Is Very, Very, Broken (Louis Gray)