It is very accurate, although about one minute delayed. I live on the approach to the easterlies at LHR. Zooming in, I can locate my house, and watch the little yellow planes fly over. The little yellow planes pass over about a minute after the real thing.
Have you ever heard the phrase "live and let live"? After 45 years of aviating, I'm still an enthusiast, and love watching flightradar24. And yes, I do have a life!