I love PCars...but I've been with it since beta (maybe 3-4 years at this point) and run it on a PC. As a complete package, it's an excellent racing game.
The majority of people who "hate" it have tried it a couple of times and given up because of a random glitch or some minor annoyance. Consoles seem to have more glitches than PC which is completely understandable since early in its development, PCars was intended for PS3/360...and was changed over rather late. They also had no crowd-funding testers for those platforms.
The game to me is a trade-off. During development I was hesitant as they announced more and more features they wanted to implement. They attempted a lot of things, and pulled off most of them. A few didn't pan out. A few they have since fixed which is nice.
Learn a couple tricks, find a few people to race with...and if some minor feature is broken, don't use it...and the game is excellent. For instance you'll learn that AI (while a bit less spastic and more entertaining than other games) think they can lean on you in open-wheelers...so AI with open wheelers is almost impossible.
Landmines are few and far between (we haven't run into any since launch but we're on PC and we don't heavily tune our cars)
The pit-stop set up is pretty poor...one thing they could hugely improve upon, but I normally don't have a problem setting up a proper pit strategy and having them carry it out when I park.
Online is online...like every game you're going to have stupid people, people without mics, non-chatters and suicide squad idiots. Find a series or a handful of drivers to run with and you'll have a good time.
Ignore the nay-sayers. The game is worth the money (particularly since it's 50% often on Steam!).