The device is currently running Android 2.3, which is good to know, because of support problem for X10, which was sold with Donut, even there was Eclair available when it was launched in some countries.
Why I am not excited?
1. It's fat
I carry my device mostly in my bag, not in my pocket, but even when I'm using the device, I don't like when it's really thick, and from current pics/videos I see that Xperia Play is. I know that the main point of this device would be gaming, so it needs physicall butttons for better experience, not the virtual/on-screen, but the size of HTC Vision would be ok.
2. If I would like to play games, I would buy PSP
I used to play gmaes on my Gameboy Advance SP, but now I don't do that so often, mostly on my PC, or just few titles like Angry Birds or Speedex3D on my Android device, for few minutes to relax. I don't see the point to buy device designed for gaming, but if I would need one, I would buy PSP, because I don't need my console always with me, as I do with my smartphone.
3. Battery is important
The point is that gaming needs juice, and in this case, having two davices - PSP and smartphone would be better, because you don't need PSP as often as your phone. And if we point that smartphones often have problems with battery life, imagine how it would be reduced with additional playing sophisticated 3D games.
4. It's... Sony
Even they make high quality products, the support for existing ones isn't the best one. Including the official one, and the one from 3rd party developers - like xda. Add to this that Sony complicates things - it took some time to get root and custom ROMs - so overall Sony isn't reliable brand when it comes to Android devices.
But overall I'm always happy to see innovative device on the market. It's also good to see Sony still working on their products to be more competitive. Hope that the Xperai Play will find fans and will not end lik Nokia NGage devices line.