It's depends...
What you like to do? This is a fun module, you can do variety of missions, but is limited just to dumb bombs, heat seeker missiles and no useful radar. It's a module of a old plane, if you like the F-5 or the timeframe he represent, go for it.
But if you dont know yet what you really want to do in DCS, I strong sugest you to use the 2 weeks free avaliation period to try it, and try modern multirole fighters like F-16, F-18 and JF-17 who allow to you great variety of missions with your friends.