The Samsung s3 - it is hyped beyond the product. The audio from the phone is not audible to the other caller and the problem comes very frequently.The s-voice app is absolutely of no use and it can very rarely recognize your words.
I have not used apple 4s for siri but I think should be much better than this. Many ordinary features like record a call and others not available. Evaluate it before making the purchase.This is entirely my personal opinion.