Honestly, if you're just getting into the sport, I'd suggest a less expensive option than a 73' or a 66' . Even though a slicked up, short stroked 73' in .38 is likely the fastest option, what you want is a dependable rifle that can teach you the skills to benefit from a better rifle. If you spend the extra money on ammo and practice you will likely get more benefit than if you just hop into a $2000 dollar gun. Another thing to think about is Wild Bunch, if you decide to shoot Wild Bunch you will need a rifle in .40 cal or above, so a .38 or .357 won't cut it. Personally I went with a 92 Rossi in .44 magnum and did a decent action job and haven't regretted it a bit.
More often than not, shooting well is more about the guy behind the gun and a bit less about the gun itself. You don't hop into a F1 car the day you get your drivers licence. Rossi's and Marlin's are among the most common guns at Cowboy Action Shoots, they are solid, reliable and inexpensive guns. All thats needed to make them race ready is a spring kit, a one piece firing pin for a marlin and some internal polishing. Just my opinion, Skokie.