I fully agree that for a novice, an Extra 300 or such is not necessary at all to learn aerobatics. You can learn the basics, and even enjoy competitions up to Standard level, in a Robin R2160, GeneralAvia F22, Slingsby Firefly, Fuji FA-200, Bulldog, CAP-10 or similar aircraft. As long as the aircraft is certified for +6 to -3G and preferably cleared for (positive) flicks, you're going to be fine for the first few years. An inverted flight system is not required either: All maneuvers up to Standard level have very limited inverted segments, and during these segments you can just be a glider.
Flying an Extra 300 is an extreme thrill, but realistically you'll be paying between two and three times more than a basic aerobatics trainer per hour. Sure, that's partially offset by the shorter transition time from the airfield to the practice area, but you won't learn your maneuvers faster, or develop G-tolerance quicker.
And, like others said, by flying in a relatively low-powered aircraft you'll hit the limits of that aircraft earlier. You have to sort things out by using (and thus, acquiring) superior flying skills, instead of having the luxury to sort things out with power.
Last edited by BackPacker; 4th July 2013 at 07:57.