If you are asking strictly about looks, then as Paige said, it will vary, depending upon what breeds have been used to get to that particular generation. In general, those breeds using outcrosses will look less servally than those using Savannahs on both sides of the pedigree. However, in general, the more generations removed from the serval the more domestic the cat may act or look, however this is becoming less obvious as we see more and more generations of Savannah to Savannah crossing. It is extremely doubtful that we will ever see a Savannah that looks like a serval, but I have had a couple of F2s that come close (look more servally than their F1 mothers) and my goal is to achieve that at the F4 or later generation.