Steve's Digicams does the most reviews.
http://www.steves-digicams.com/hardware_reviews.html
The reviewers usually get to see the new cameras as they are released and shown at major camera shows.
That does not mean that they are available for review or testing.
The cameras shown at the major camera shows are usually prototypes and the camera makers will not permit testing of prototypes, and will not let the reviewer post photos taken with a prototype.
The reviewers usually don't get their hands on a real camera until they are available to the public.
With all the new cameras that were introduced in February, it is going to take a while for the reviewers to catch up with the flood of new cameras.
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Among trustworthy reviewers, is there any site that usually has info and evaluations of a new camera soon after it is launched?

Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic