It's not too bad, but being as much of the data is "user" generated
ADS-B data, there are quite a few gaps and missing planes.
Also the delayed FAA data is incomplete compared to say Flightaware's
delayed FAA data.
I can compare FR24 with Flightaware in the Houston area, and
Flightaware will almost always show planes which are missing on
FR24. I'm watching both right now, and there are planes lined up
to land on runway 4 at Hobby, and a SWA jet from New Orleans
crossing the city to turn around and land on 4.. He had to run north
a tad to dodge some storms east of Hobby and Ellington.
They aren't even showing on FR24..
So.. I tend to prefer the maps on Flightware even though all planes
have a slight delay being they are using FAA data.
The Flightware page for KHOU.. And you can pick other airports or
flights for comparison with FR24.
William P Hobby Airport (Houston, TX) KHOU / HOU Flight Tracker ? FlightAware