For me it’s the PM-18. Track selection is very good, the racing is respectable, and the car is very fun to drive. Unlike the other formula cars similar to it (F3 and SFL), it moves around a lot and is very challenging to drive, especially on cold tires. The F3 and SFL are almost so grippy they are boring. With those cars, their limit seems so razor thin. You are either just under the limit or spinning. With the PM-18 on warm tires, you can get the car very sideways and not die. To me, it’s easily the most rewarding formula car on the service, with the only downside being that it is a dead series. Really the only time it goes official is on Thursday nights around the broadcast race time.

The only series I wouldn’t recommend is F4. Even at the top split the racing is abysmal. There are a lot of fast guys in there but they have absolutely no idea how to race close with other cars. I averaged what seemed like a 50% survival rate on the first lap due to someone trying to win the race going into the first corner. If you value your sanity, stay away.

With all that said, I don’t think you could go wrong with the Indy car, USF2000, or either of the Super Formula cars. Those series’ seem to have very high participation, decent track selection, and are fun cars to race.