You are already flying what I'd suggest for a second plane. The Somethin Extra is a real nice flying plane but not what I'd consider for a novice, you might consider it after several more flights on the Big Stik! I would add it to your inventory if you can, but don't get over anxious and risk taking the ding to you pride by jumping into it right away. Just be patient and get another 30-40 flights at least on the stik, and even then you might consider another plane with less dihedral than the stik on the wing or no dihedral at all. The Hanger Nine Ultra Stick would be a small step up from the Big Stik due to the flatter wing and somewhat better aerobatics, Tower's Kaos might work for you also. Just my suggestion. There are always exceptions, and your skills may allow you to make that change without incident, but the odds are against it.

Good luck,
Sargent