Forza 5 at launch was my favorite in the series. Because you actually had to buy low level cars so you could run races and win races, which got you enough money to buy slightly better cars, etc. It was a return to climbing the ladder towards better and better vehicles. Telefrog and others called that “grinding” and hated it, because in order to get to their preferred Ferrari or whatever they actually had to play the game in other vehicles first.
However, there was such an outcry that they re-balanced the rewards to be more generous, so you didn’t have to play very long to get to your Ferraris and Bugattis and Lambos. Just like every other Forza game after the first one.
The other reason I loved Forza 5 the best is the Drivatars. At the right difficulty levels, the way they raced was so much like the person they were emulating. Like I would watch my brother play, and then later I’d be alone at home racing against his drivatar, and it was like playing asynchronous multiplayer because his drivatar drove just like him!
People hated that too. They said the drivatars drove too irrationally, and it wasn’t fun because blah blah blah. Vocal fans have to ruin everything for the rest of us, I tells ya. Anyway, I think Drivatars are still mostly the same in Forza 5, but I heard they’ve been neutered in Forza 6, just like they were for the Forza Horizon series. So I think Forza 5 is still the best in the series even post-patches, even though it’s not as good as it was launch.