Too much power is not a good think when learning aeros, and I would recommend the DHC-1 or Buldog to start with and then move on, it is vital to get your techniques right before too much power masks your lack of training.
I find the DHC-1 a more difficult aircraft to aerobat well than the Extra 300 and an very pleased that all my basic aerobatic training was on an aircraft that rewards good flying and tells you that you are not flying well without biting you too hard.