Get iphone 5s or wait for 6?

At the moment i have the 4s but am looking for an update, to me the 5s looks quite good but i'm unsure wether to just wait until the 6. Does anybody know if the 6 will be much of a difference or how long until we can expect to see its release?

If your all the way back at 4S i would update to a 16gb 5s. The 6 will have a larger screen and a faster chip i would say its a lot better thats why i would not invest a lot in the 5S.