You might want to buy Mike Goulian's stuff to get a view from a pro - Basic Aerobatics and Advanced Aerobatics are both great books, written in very informative yet easy going style (forget the AOPA book - it's technically fine, but otherwise awful in comparison).
In both books he discusses the merits of starting off in slower kit, and there's plenty of great stories from the history of aerobatics to balance out the instructional stuff.
Personally I'm flying a Robin 2160, done my AOPA (well, all bar the sequences), and now having a similar dilemma - do I step up to a CAP10 or Extra 200, or I do aim for perfection on the 2160 first?