The fact is I don't care which game is better, I'm just a victim of availability. For example, I own a PS2 and are about 80% done with GT4, by for the last 4 weeks my friend let me borrow Forza and his XBOX while he was moving.
I played Forza to about level 32 and realized that while its a good racer it has its flaws, like GT4. It seems the interface in Forza has some interesting bugs, including the lack of being able to tune cars before a race, or qualify so you can warm up for each race. It seems Forza requires you to adapt almost instatly to every car and track, and it requires that you set up your car with a uber setting, that can handle anything.
But GT4 isn't exactly better. The lack of any variety in customizing your car in GT4 makes it more bland. It seems that in GT4 every car is the same, at least until you get on the track. The lack of any body mods or paint change makes everything very dull, as some cars are limited in color selection.
Forza on the other hand has a very big problem with actually understanding tuning physics, and it's much harder to actually test out your tunes in Forza. GT4 on the other hand limits your tuning, but also lets you understand what is going on by allowing bigger steps in adjusting let's say suspension settings, especially the anti-roll bar and bound/rebound settings. It also allows to adjust TCS, which, contrary to popular belief is very important in racing, especially for race cars.
Forza however has a very cool telemetry engine, which if the casual player was a mechanic, would help out tunning, but alas we are not all created equal.
In conclusion, because this is taking too much of my precious time, neither game can be called the best racing game, because neither of them actually achieve something close to perfection, they both fall short of expectations and require the users to spend too much time playing them.

This is one of the most fun games I ever played. It's probably the best uses of the Star Wars lincense I've ever seen. I think I will beat it 3 times, I already tried the light side, now I'm playing as the dark side, and last I'm going to be a scoundrel light side. I think being lights side is harder than going to the dark side.

Yes, I know a few of you out there cheat, or better yet hack like crazy, but I really don't understand why. Is it for the attention? Or is it cos' it's fun? I really don't understand the logic behind it. I mean, you bought the game to play it, not destroy it's whole concept. Maybe it's just a Microsoft conspiracy, especially since CS:S is probably grabbing away gamers from HALO. But still, if you hack, your a coward and an a-hole, and don't expect any sympathy from me when they ban your sorry butt from every server on the net.

GT4 is an awsome game if you ignore some of its flaws. First off the music is horrible. There are maybe two good songs in the whole library that the game provides. I woulnd't of minded the old soundtrack from GT3 but after over a year of delays you'd think they could do better.
Another problem is the A.I. it's so clueless of your car. It's like your car is invisible most of the time and they hit you without hesitation.
Arcade mode used to be cool but now its stupid. The only reason you would even do it is to play multiplayer. And why can't they have more than six car in a race? You'd think with the PS2's hardware you could at least get two more on the screen, it's dissapointing really.
Another disappointmen are the effects. While the basic effects are fine, what about a blue tinge to the exhaust when you use nitros, or maybe some actual tire marks in the grass. It seems that i've played older games that had better effects than GT4.
Well now that that's settled, everything else about the game is awsome, especially the car physics. I haven't felt so into a racing game since GT3. Especially when you brake, the dive feels so realistic.

Winning Eleven 8 is a awesome game, but playing at six star difficulty, is amazingly hard. The computer cheats like crazy, especially with the referee. He doesn't call most fouls against the players, and if you as much as step over someone legs you get yellow carded, while the computer does horrible slide tackles in the box, and gets away with it.

Well I started this game a few days ago, and have played about five hours of it , and it's almost over. The game seems to easy, and you can beat it with all the secrets unlocked without a strategy guide.