The Atlanta Symphony, although many of its programs are the tried and true, also features lots of contemporary music by 21st Century composers. That's it's greatest strength, in my opinion. The musicians are excellent at whatever they do, but some of the contemporary works appear to me to be very difficult to perform, and not only because they are new and pretty much unheard before.
Also, the Chorus is one of the best in the world, and anytime they are performing, it's a special evening.
Go hear them. If you like classical music at all, you won't be disappointed