It's always an emotive subject within the flight sim community but it really comes down to which faults in their sim you can live with...
If you want flight model accuracy then no amount of eye candy graphics will scratch your itch...
Maybe flight models accuracies all very well but unless the graphics grab you and immerse you in the moment it's no good for you.
Maybe it's playing online with other people from around the world, but flying a bomber like an airliner just doesn't cut it for you... or you feel an online game should have 100's of players in the arena rather than a handfull.
Or could it be that you like squad nights, working as a team playing in organised events.
Maybe you're the sort of guy that likes to add extra's to the sim, like sounds, or particle effects or even create your own planes.
Or you'd preffer to buy a 'finsihed' boxed sims, and their subsequent releases/improvements with free online play over a free sim with subscription online play that has a continual WIP feel to it.
But check out Ace's High..(subscription online)
Warbirds (subscription but free online play for the next 2 months)
Targetware (player contributed and free online play)
Picking a sim is not as simple as it first apears.
Regards
Simon