It depends on what type of plane your after.
If A2A then i recommend the Mirage.
If A2G i recommend either the A10c or Harrier
The F5 is a cracking plane but a2a its limited to two weapons and mainly against the mig 21, where as the mirage can carry BVR weapons.
The harrier and A10 are the only A2G planes worth it tbh, the harrier is easier to learn and more fun
If your looking for any help with these planes we have over 350 members all of whom, will happily help where they can :)