Its a lot of fun.  The close-in guns-only dogfights are worth the price of admission.  The graphics are better than average and the damage models are fairly advanced.  There are LOTS of add-ons available since the sim is open source.  Best of all, most add-ons are very high quality.  These include paint jobs, new terrains, new weapons, and lots of new airplanes.  Make sure you load the first patch.
MiG