the poor accuracy stigma has followed them through the years. Add to that the fact that the factory has always limited thier hi caps to law enforcement and you have a mediocre reputation.
I've owned 2 (one 188 series and one 580 series) and they have both been very acceptable shooters. I have never had a single malfunction that wasnt related to aftermarket magazines either. Now I only use factory mags when it counts.
The new model 580 series is a great gun and you can expect to see 2" groups with decent ammo. If one were to add one of the clyde armory socom railed aluminum stocks like the m14, a flashhider and factory mags, and you'd have one of the most reliable capable 556 guns on the market. I'd put it up against a stock sig, AR, Masada, and XCR in a long term shootout. It may not win, but it'll do better than folks give it credit for
If I could change two things it's be to add a chromelined bore and a threaded barrel from the factory.