i got 3 chioce now

1.sony p1i
2.sonyK850i
3.c902

which better?

you comparing the EOL model...
roughly.. those 3 phones arent good either..

well talking about function and features...,sony p1i is better..[because it has wifi]..

but well talking about camera performance.. SE K850 pawn it all..[although C902 seems closer]...
my advice.. dont buy any model above.. it is EOL..better buy new phone with better features.. i suggest SE Elm[RM 600]

The SE P1i is more business-oriented and is a smartphone, with 3G and WiFi, but the camera is horrible.

The K850i and C902 are both featurephones. They lack WiFi but have a great camera.

So depends on what do you need. If you want a great cameraphone then I'd say the K850i because it has a larger screen as well as Xenon flash. If you want a more capable phone I'd pick the P1i because of its WiFi capability as well as its Symbian OS. Do note that the P1i does not support WPA2 WiFi security.