Hi Adam,
I have both an Aspera and a just-finished Sebart Wind 50. I too bought the Aspera because I wanted a precise flying sport plane, and maybe one I could start competing with. While I can't knock the Aspera in any way, it's just a small airplane, and istakes work to keep on line on large maneuvers, especially if there's any wind at all. Not impossible by any means but you really have to keep on top of it. I finally got a bit tired of it and wanted something bigger so went to the Wind.
Even though the Sebart Wind 50 is really not all that much bigger on paper, I can tell you they are completely different animals... the Wind tracks far better and presents much more gracefully than the Aspera. Frankly my impression is that t's less exciting because it's not as fast responding as the Aspera can be (the Aspera can snap so fast you can barely see it!) but for precision and grace this is a good thing. At this point there's no looking back for me. If you really want a serious performer, I'd go straight to the Wind (or something equivalent in size).
PS Bought mine from Chris at F3A Unlimited... he has a great package deal and has a lot of information if you ever need advice. And great stickers too
Let us know what you decide!!
Rick