Well, forgive me if I don't find that anecdote terribly convincing.
Got any more specific details for us?
I must say it would appear as though GT5 looks way way way too easy because I haven't seen any "level 40" or whatever videos yet. I always play Forza 3 fully maxed difficulty (bonus cash 100% yay!), and always in cockpit mode, and it's difficult to imagine a much more difficult handling model for most of the cars at speed. The way you must carefully manage understeer (as well as the more customary oversteer) makes it pretty unique amongst all racing games. Admittedly it doesn't match some PC games.
Forza also has one really cool advantage I have yet to encounter -- 99% of the cars are utter rubbish untuned. Specifically springs & dampers; it feels like GT but far, far more cerebral. You stiffen up for transitional steering control and then adapt to what the tires will allow. It really feels a lot more convincing than GT ever did. I hope GT5 can add to this (originally their) legacy! I played the first three GT games to about 99% completion, and well, I'd say I'm very bored of GT, but I have high hopes! Now to find some videos with whatever full physics complement unlocked.
My dream game is stocked with a near-complete list of normal-people cars; this is one area in which GT excels (rather unevenly, but better than the competition). I think almost everyone wants to race and tune what they own or people they know own -- why would I care whether I have the 2008 or the 2009 LM DB9 racing model??
GT5 clearly has a fantastic replay and video mode. That's a real must in a racing game and Forza's pretty much sucks! And of course after a few months, it's hard to find motivation to press on in F3. I spend more time these days modifying and painting/decalling cars than racing these days, because the racing is brutally long, and the vanity shots are very, very, very beautiful...