If you're interested in aerobatics and truly want to skip the "second plane" stage, I'll suggest a Tower Hobbies Kaos. It's very neutral handling and can do any maneuver you can think of aside from 3D flying, but it also avoids the tip stall tendencies that many of the IMAC planes will have (like Extras, Edges, etc). That said, a Sig 4 Star or any Ugly Stick will let you advance your skills a lot and fly the vast majority of aerobatic maneuvers and will be more forgiving of piloting errors, especially stalls. Later on, it will be your windy day plane or will come out when you're just in the mood to bore holes in the sky instead of think hard about flying a scale warbird or serious aerobatics plane.