he posted that before I even posted the whole comparison. But I'm pretty sure he was just in a "anti sony" "anti-anything-that-isn't-the-pandora" mindset at the time.
I have mine in airplane mode 100% of the time, I don't use the phone functions at all. To me it is just a android gaming handheld. I don't know how else to express that this is capable of being a phone if you want it to, but doesn't have to if you don't want to use the phone functions. It works either way.
(BTW you can put airplane mode on and still enable wifi and leave the phone/3g off)
with my config I have a 3600mah extended battery play in wifi only mode, and 4000mah battery pandora in wifi only mode and I see very comparable play times on each approximately 10-12 hours actual running time. Stock battery you are looking at about 4-5 hours of pure gaming on the play.
Have to say I'm not a fan of Sony phones. My last Sony branded phone was the W800i - the first walkman phone that came out years ago. The firmware was so bugged it would crash and completely lock up - I couldn't even turn the thing off by the power button, and literally had to pull the battery to turn it off. It even did that after a firmware update. After that experience, I vowed never to buy another Sony phone... I most certainly prefer HTC handsets - beautifully made, intuitive and with Sense UI. Most of my mobile gaming (via FPSE PSX emulator) on Android is via an HTC Desire and Zeemote JS 1 bluetooth controller. I just hope HTC release a handset with joypad controls built in as then I would buy....
Best phones right now with regard to pure grunt are the HTC Sensation and Samsung Galaxy S 2. Pure monsters with 1.5Ghz dual cores. Just a shame they have no gaming joypad.
Edit:
As for battery life on the Xperia, try installing JuiceDefender off of the Android Market. That hugely increases battery performance I have found. You could possibly squeeze a bit more juice out of the battery by lowing the brightness.
After reading on forums, the biggest impact on the battery regarding my phone which is an HTC Desire is the flashing orange LED which comes on when the batt is low / or when an SMS arrives. So turning that off helps too.
I'm a huge android fan if you don't keep up with my previous postings, I've owned multiple htc devices hero, evo 4g and most recently evo 3d, I've also owned a samsung device, epic 4g... while I agree htc devices are beasts with their raw power and excellent contruction. however I almost loath samsung's hardware, the specs and hardware they choose are nice, but their firmware, be it their fs they use (propriatary to their non-downgradeable radio firmware, bricked my epic trying to downgrade to stock) are absolutely frusterating and I'm at a point I will probally never own a samsung device ever agian.
I have had my fare share of sony hardware also, psp, mylo, walkman... and I agree the os's they choose are riddled with bugs and security holes out the wazoo, android on a sony device is just fantastic, they almost literally couldn't screw it up. While their bootloader is non-standard, they allow you to unlock the boot loader to either fix what you don't like or use standard android development tools to reload or tweak to your hearts content. I have not ran into the similar frusteration in non-support or bugginess with their flavor of android.
juice defender works if you use the device as a phone as it mainly just cuts off the continuous data connection and just turns it on momentarily througout the day, if you use the play as I do with wifi on only when needed and cell radios off most of the day then it is a non issue. Auto dim screen is on by default so that is not an issue. Overall I'd actually say the power management is superior to htc or samsung as most of the stock constantly running services you get with those devices don't seem to be running or much of a hinderence. Custom roms are useally needed to get a decent daily battery life out of your device, this is not the case with the play.
being a veteran android user the play stacks up as one of the best I've ever gotten the pleasure to use.
EDIT: my one complaint, if you could even call it that is that the native ps1 emulator has not been hacked yet to run backups of your ps1 discs.... now that might actually be a complement to sony, strengtheing up their security on what was not meant to be exploited.
They got some serious talent on trying to crack it as it would probally lead the way to a native psp and ps2 emulator when those are released as promised, but their attempts to break the code have been unsuccessful so far.