Forza has online play, that right there makes it better than GT4. Those 2 are the leaders of Racing sims, and when Forza came out it just took the lead. We'll have to wait until the PS3 and the 360 to see what they come out with next. I expect both the newfound Forza series and the Gran Turismo series work extremely hard on their next project to beat out eachother. Before when GT was the ultimate Racing sim with no contest they didn't have to do much to their games to make them better because at the time they were the best. All they had to do was update the cars really and add a couple more, but now With Forza expect them to make their next one over the top!