Crash damage in the form of bent rim outers can also be repaired. The payoff in forged wheels comes in weight and durability. These racing wheels certainly cost more, but are generally stronger and lighter than an equally-sized cast wheel. Plus, their multi-piece construction allows for custom offsets and the opportunity to be repaired as needed. And while we're on the subject of repairs, we should mention wheel failure.
Few things can be more catastrophic than a wheel coming apart on a race car.
Wheels used for racing can be checked for cracks using inexpensive dye-penetrant kits available from racing suppliers or aircraft tool supply outlets. This treatment should be done seasonally at a minimum, and certainly after any incident that you feel could have damaged a wheel. All right, back to picking what's best for you. Let your type of racing and vehicle be the judge. If you have a heavy GT1 Camaro, cast wheels are probably out of the question.