RE: parkzone difficulties?
The big difference is speed. Warbirds are fast. Trainers fly slower, giving you more time to react. Slower flight may also mean less damage in a crash -- and you WILL crash.
Trainers are designed to be very forgiving. For example, when you take your fingers off the sticks, a trainer will tend to return to level flight. This won't happen with warbirds. They tend to keep going in whatever direction you point them -- you have to maintain active control at all times.
I'm sure there are some pilots who can start with a warbird and make it work. You may be one of them. Whatever you decide, good luck!
- Jeff