Sony Ericsson Xperia Arc S uses the Android 2.3 Gingerbread by Qualcomm’s support single-core 1.4GHz processor, while the LG Optimus Black uses the Android OS 2.2 Froyo with 1GHz single-core processor support.
LG Optimus Black comes with a 5 megapixel camera and front camera 2 megapixel camera. While the Sony Ericsson Xperia Arc S is equipped with 8 megapixel camera with the ability to take 3D images and 720p HD video recording, and come equipped with front camera. Optimus Black LG and Sony Ericsson Xperia Arc S both have a capacity of 1GB of internal memory and microSD slot support up to 32GB.
Sony Ericsson Xperia Arc S has better specs than the LG Optimus Black. And of course the price of the Sony Ericsson Xperia Arc’s more expensive than LG Optimus Black.