I can't believe I almost didn't buy this game. I had read a lot of nay-saying about the physics and handling being unrealistic/floaty that almost stopped me from shelling out the $60 on it.
Let me start of by saying that I am a die hard racing sim fan going back to the days of Nascar 1 back in '94 and have just about raced them all, and I am a stickler for realism.
I race with a Logitech DFGT wheel, recently upgraded from my Logitech Momo, and what a difference. On that note, If you are having problems with the force feedback going away after one race on your Logitech wheel, you must read paul's post here:
http://https://www.gtplanet.net/forum/showthread.php?t=196575&page=8
I was extremely frustrated with the handling until I applied the fix, and now I couldn't be happier. The physics in this game IMO are at least as good as those in GT5. And with the DFGT wheel with 900 degrees rotation, it is a blast to drive.
I find the immersion of the game to be absolutely top notch. The sounds of each vehicle are spectacular, as you can hear the high-pitched whine of the turbos, to the low growls of your V8, rumble stips, unspent fuel being burned off, ruble from the road being kicked up on the bottom of the car, it's just incredible. I race with the traditional cockpit view, I do love the helmet cam but I can't seem to roll out of the exit of turns properly when the view is changing, I always feel like I'm about to spin out. The sense of speed is very realistic when you combine the sounds, handling and view. It's just a great experience.
I find the AI to be very good. I race on elite handling and hard AI. It's nice to have a challenging race every single race, with the exception of the endurance races, as I will normally break out at about lap 8. The pack normally stays pretty close, so you don't get the runaway 1 or 2 cars that you get in GT5. They will give you room on the track, but also challenge you in to a turn, trying to outbreak you when they get the chance, or take a blocking line in to turns. Don't be surprised if you get a tap in the back if you are a little too conservative braking in to a turn. The GT1 events are very tough, as you nearly have to race a perfect race to win, or to even finish in the top 3.
Some of my favorite moments have been taking class D or C cars on Nurburgring or Bathurst, as some of the turns are great with the DFGT on 900 rotation. You really have to throw the wheel around and feeling the wheel naturally return to center exiting corners feels very realistic. Finding the right rhythm on Nurburgring can be a blast and a truly rewarding experience. But get it wrong and you'll find yourself spinning like a top, or rolling over and over.
If there is anyone out there who comes across this post and is still undecided on whether or not to buy it, do yourself a favor and do. I am addicted, and I can honestly say that this will be my go-to racer from here on out. I will still use GT5 when I want a nice sunday drive, but I've got to hand it to SM Studios. GT and Forza better watch out, because there is a new slugger in town.