RE: Next model after the Big Stik
At this point the sky is litterally the limit for you.
You'll be tempted to move to larger aircraft over time, so think ahead a bit.
What would you prefer MOST? An Extra, or a YAK for instance?
If the Yak ( good choice ), save that for later when you can purchase it as a larger plane.... and use the engine on a 40 sized Extra now.
That way you will not feel that you may be looking at ANOTHER version of a plane you already own later.
I think a 3D plane offers a different challenge which you will enjoy.