About a month ago
I just found the handling much better, drift transitions, simulation of how a open, limited and locked diff, plus it was also the first game I remember to model automatic transmissions properly, as in the slushy-changes. It also had a massive long straight on a never ending bridge, and featured wet weather (and it handles a lot more realistically in the wet than GT5 does) and dirt tracks!
There were loads of cars as well and a good variety of them. I found Enthusia to be more fun..
I'm not saying GT5 is bad just that with a gamepad I think Enthusia is a better sim. With a wheel GT5 is mega but still, for examle the fact all the cars on GT5 have rubbish brakes and you CAN'T UPGRADE THEM (wut)...lacking in many areas. Plus ability to upgrade bodyparts.
Golf Mk5 GTI on GT5 for example, there are no body mods, no racing conversion available, where as you could in real life put the ED30 kit on.
I think GT5 is a better drive than Forza 4. It also has nicer graphics. Forza 4 has more customising options for example tuning and appearance. Enthsuia well it's a bit old but for me in terms of outright simulations it's still up there.