After reading some of the articles on N4G I feel compelled to do a comparison piece because some of the comments and reasons given are pathetic. I'm level 32 on GT5 and 62 on Forza 4, the reason I'm not level 40 on GT5 is because when I was making space on my hard drive for my free games off Sony I stupidly deleted my save file and had to start again. But I think level 32 still makes me qualified to give this comparison a fair go. I race with a Fanatec GT2 and I'm pretty sure half the people who talk about physics on this site race with a pad. I'm not going to talk about graphics because they are irrelevant when it comes to racing games. I will be comparing things important to a sim racer. If you think you are a sim racer and you race with a wheel read on, if not and you race with a control pad. Then your opinions mean jack.
When it comes to physics both of these games fall short when compared to PC sims but they do a god job considering the limited consoles they run on. Both games do a good job of simulating how a car reacts to input from the driver and both games do a fairly good job when it comes to set up options for your chosen car. You can change camber, toe, ride height etc. on both games. In my opinion Forza does a better job when it comes to physics, I can feel more through the wheel. I can feel the under steer building up and you get a good feel of how much grip the tires have. With GT5 the feeling is mute, the wheel has a good weight to it but that’s it, there is no feel for what the car is doing, you have to judge visually and through sound rather than feel what the car is about to do. To me that is what makes a good car, the amount of feel and the connection with it. If you can't judge what the car is doing how can you have the confidence to drive it fast? GT5 is a good game but the real driving simulator needs to concentrate on driving, not on getting the right stitching on the leather seats of premium cars.
Another important aspect of racing is sound, if you love cars you will know what I’m talking about. The sound of a V8, a straight six and a V12 are my personal favorites and a racing game needs to get this right, GT5 doesn't, the cars sound electronic and not at all like the engines they are supposed to be. Forza on the other hand sounds stunning, V8's sound like V8's and V12's sound like V12'S. The tire noise is also some of the best I have come across. You can hear when they are about to lose grip and when you are pushing a bit too hard.
Forza is also the choice if you race offline, the A.I are far better at racing than GT5's counter parts. They will overtake you, make mistakes and generally feel like they are being driven by another person. GT5 on the other hand feels like the A.I cars are following a train track which they rarely move off, which makes for very straight forward victory’s which isn’t realistic. GT5 does include night racing, weather and a really good rally mode which I wish they would have put more effort into because the driving model is excellent. But there isn't enough races to make it a substantial addition the game, it just feels like an afterthought. The night racing is good but the rain effects are poor. Colin McCrea 2005 had better rain effects last gen, again it seems like they just added it right at the end just to get it into the game. Wet roads don't look wet and the spray off the tires makes your car look like it’s made of heat haze. I remember the Tokyo track on Forza 1 which was set at night, so I don't get why they couldn't include night racing in 4.
The selection of cars is poor on GT5, there aren’t enough new cars. The Bugatti Veyron is standard, yet they have made the Suzuki cappuccino premium. Forza's selection is much broader, you have an abundance of new cars like the new Ferrari FF, Gumpert Apollo, BMW M5, 599 GT0, Aston Martin ONE-77 and many more and they all sound amazing. I also might add that this is the first game to nail the McLaren f1 engine sound, which is a big plus for me as it’s my favorite engine sound ever.
My winner is Forza because it feels better, sounds better, and has more cars that I want to drive. GT5 is a great game and if you only have a PS3 then you’re not going to be too disappointed, if you like racing games though, I would highly recommend getting a 360 and Forza 4.