Sam Byford, writing for The Verge:
Sony just took the wrappers off the PlayStation 4 at a blowout event — but something was missing. Bizarrely, the company elected not to show any glimpse of the console hardware itself, instead focusing on internal details and a showreel of upcoming games.
Not only did Sony fail to reveal the actual hardware design for the console, they also didn't announce a price or release date. The lack of pricing and release date information makes sense at some level since they want to be able to react to Microsoft's next Xbox announcement, but not showing the console's hardware (beyond the new controller) is downright odd.
To be fair, Sony did show some interesting stuff. Of course, it all starts with games, and Killzone: Shadow Fall looks beautiful. The integration of Gaikai's game streaming technology seems like it will open up some interesting possibilities. Likewise, the integration with mobile devices (e.g. smartphones, tablets) is something that just makes sense.
Overall, Sony did okay with its PlayStation 4 announcement. Not great, but not bad.