Free Falcon 5 official site
http://www.freefalcon.com/forum/index.php
Open Falcon 4.7 official site
http://www.f4support.com/forums/index.php
Free falcon and Open falcon download site without requiring registration
http://falcondepot.info/
http://falcon4.0files.googlepages.com/falcon4.0files
Open Falcon 4.7
I have only tried Open falcon and it's a very realistic game/sim, even more realistic than Allied Force. In fact, it is the most realistic F-16 sim anywhere you can get your hands on.
However the realism deals a lot with the avionics functionality such as manual radio tuning, data cartidge, data link and much more.
So the realism features are mainlyunder the hood until you learn about them.
Installation requires the original Falcon 4 disc.
Free Falcon 5
I have never tried Free Falcon 5. Still downloading it
Installation doesn't require the original Falcon 4 disc or so I've been told.
Realism is subpar compared with Open Falcon but it has got a shinier graphics and better F-16's 3D cockpit. However Open Falcon is known to be the more stable of the two.
You can play both game on Vista but I don't think they will run on Windows 7.