I am currently making the same decision. I tested both the sonare and the signature and found that there was a subtle but definite difference between the two, with the signature slightly better. However, I too am not sure that the difference is worth $1000. My teacher has an adult student that has a sonare and loves it, but she said that, at least for this student, it plays quite sharp.

I also would like to try the newer amadeus flute, but they are not available in this area.

good luck with your decision.

Amadeus flutes can be purchased at http://www.fluteworld.com/ This is a reliable website and I believe it has a trial program if you are interested in testing it first.