First off, are you considering an ARF or a kit? Either way, a good way to get into warbirds is with the 'FunScale' ones, such as the old DynaFlite FunScale warbirds, and current Great Planes ones. They can be made into fairly good looking, yet great flying aircraft which will help you transistion. I personally have a DynaFlight FunScale 40 Corsair, which was my first warbird and is now 7 years old. I have since built and flown the Top Flight Corsair, and the experience that I gained with the DynaFlite one was very helpful and made the transistion easy.
Flying warbirds requires you to become a good rudder pilot, but with a FunScale one it becomes easy.
Good luck, no matter what your choice.