When I go flog the car in the twisties (inb4 != wrx), the simulated shift points function great about 95% of the time. The car seems to do decent with holding the high RPM, and I've only had it refuse to downshift 2 times before when I thought that it most definitely should have.
Keep in mind I drive this thing harder than most people, and can't really see any issue with how it performs, all things considered.
It's great to slap it back into D after that and have a leisurely and comfortable ride home.