The 2 stars I gave this are entirely based on the service, independent of price. If price is not a factor to you, then iRacing is a great service. It is about as close to realistic as it gets. There are minor complaints, mostly revolved around connectivity issues. Races have often been ruined by someone just blinking from having a poor connection. But those are minor issues, something any game will face.
The price, or system of pricing, is what makes this simulator frustratingly difficult to recommend. It's a subscription based service, which is expensive on it's own. For 1 year, it's $100. At this price, all content should be included. It's not. I'm okay with DLC, when it's not something the game needs to function. As you progress through the rankings, you will find that weeks go by where you are unable to join a single race in the iRacing series because they require content. The amount of content included with the simulator is enough to get you out of the rookie classes (might take a month tops) and nothing further. If you want to use the service that you're paying for, you will NEED to spend $100 minimum extra on DLC. I've already spent nearly $50 on dirt racing DLC and I still have weeks go by where I'm unable to join any races because the tracks scheduled that week are not included with the simulator. It's not cheap either, at $12-15 for EACH car/track. This is outrageous and overpriced. It's insulting that iRacing forces you to spend more money on content just to progress through the rankings. The most common justification for this that I've heard is that it's a simulator, not a game, which is true. HOWEVER, other simulators with comparable physics are nowhere near as expensive. I can NOT recommend this overpriced simulator.