In my personal opinion , 4 way more better to buy than 4s , if u want to save money. 4s has Siri , but soon it will be on all 3gs + models ,so there is no big deal about waiting little more. Also better camera and 1080p video is cool feaure , but still thats not it , i dont like camera , i saw some other smart phones , and iphone cant compare to them. I will really question myself if i am going to buy 5s , because i wont trust in future core model of 5. Apple always screws smt in start ,so when 5 comes out , imo dont buy it.
Only one thing i would buy 4s for is that it has range now of 64GB. My music is kinda large , around 60,70 MB per song , so i really need memory.