Just done my first race, the system itself seems good, maybe I was just lucky but a short wait then short warm up is just right. The actual format of the race itself is awful, 10 cars and a 20+ minute is not what beginner racing should be about.
Off the start line I had to bring the car to a complete stop because both cars in front of me either stalled (not sure if that is possible in iRacing) or didn't bother reacting to the lights. After picking a way through, into T1 I drove straight into the back of a car driving round at pedestrian speeds, partly my fault but this guy was going ridiculously slowly. At that point it was effectively race over, damaged car (but still drivable) and lost the best part of a lap recovering.
Later on the muppet I hit seemed to be less damaged than me and caught me up with some interesting understanding of the concept of overlap took me out twice in as many laps, I think he genuinely was clueless about what is and isn't acceptable but given the ban on sorting things through chat there's little one can do to try and explain. After that it was just an exercise in limping round tripping over cars limping slower and being lapped. Only 3 cars finished the race on the lead lap, and only the front two cars seemed to have a race.
There also don't appear to be any blue flags in iRacing which leaves it a bit of a guessing game who is in your mirrors.
It also appears it is only one race every two hours