Hi Walkabout,
Why do you want to do aero's? Thrill seeking? .... no? well at least I hope not. Frankly, judging by some of the replies you've had I wonder if that isn't what motivates too many
Aerobatics are about fine tuning a skill, about getting the best out of both yourself and your machine. They are about grace, finesse and dare I say it ... they are Art!
If you trully want to learn how to be aerobatic then you must first trully know how to fly accurately and with panash. People saying that landing a Pitts is just "the dull stuff" is like telling you that a well balenced oversteer in a rally car is just "going around a bend" Find a true aerobatic pilot and he won't say that he considers a C150 not to be aerobatic; he might say that it's not really competitive any more, but he'll never say the former!
Don't worry if your mount is a lowly 150 if that's in your price range. You will learn a lot in anything with the right instructor. Indeed, CAP10's, Pitts ect ect are fine aerobatic aircraft ... but ask yourself if they are not too good? what will you fly after? Will it be a small homebuilt? a Chipmunk or something similar? Will all that power, those crisp roll rates ect teach you about power management, adverse yaw with large control inputs and all the other problems. They will flatter you and make you feel like you are good ... but will you be?
So, my advice is firstly, find a good aerobatic instructor who will teach you ... not just show you. Secondly, don't be swayed by those who think aerobatics are about sexy aeroplanes and impressing the girlfriend. And thirdly, well .... do it because you really want to but do it properly
Have Fun
IM