I own it for over a year now. I am not too sure how I feel about it because I have wasted a lot of time trying to perfect the phone.
Cons:
For the price I paid... I got very less internal memory and RAM... total rip off. (Link2SD helps but performance is not as good as it shud be)
The phone becomes slow after few weeks of installing a new ROM.... contacts and messaging takes about 5 seconds to open up. (Solved by installing Arconium ROM)
WiFi is very weak... my dads ZTE Blade (1/3rd the price) catches it better than the arc. A known issue. Drops at times.
Crack in the housing near the sensor.
Fingerprints allover the body... especially if your sweating!
NO FRONT CAM!!!
PROS:
Best looking fone ever. Beautiful design
Great camera. no matter how much people complain about JPG compression... the camera totally rocks esp under low light.
Music is good and speaker sound is loud. So is the earpiece... well done!
Phone reception is top notch!
Sony's android UI is fantastic!
Screen is pretty decent.
Battery life is the best you could get on a smartfone... it was a surprise!
to summarize, I have tried many ROMS of GB and ICS and I have found my arc to perform best with Arconium GB ROM and supercharger installed.
Performance however is not as good as the price I have paid for it. I wouldnt have complained if the phone was not that expensive.
My next phone... Galaxy S3 (with Xperia launcher) or Xperia Hayabusa...