I know this game is a hog and I'm not expecting to run at ultra settings but would I be able to have good performance at medium/high settings?
Slim chance for that, unless flying over water. The devs hope to dramatically improve performance in the next patch, we'll see...
How is the sim in it's current state?
For offline flying it's still hampered by poor campaigns, non-working radio comms and often questionable AI and FMs.
If you're interested in online dogfights there's a small but dedicated community on a handful of servers.