I am looking to buy a step up flute. My original flute was an Armstrong 104-long ago and far away in school. I still play weekly in church and am looking for a step up flute. I don't need anything terribly fancy. I have been looking at Jupiter 611, Pearl 771, Trevor James Privilege, and Armstrong 800. Any thoughts?

try those you listed and see what you like best, try it blindfolded

I would add a Yamaha 200 series to that list for sure. It really IS a step-up flute even though it is marketed as a student flute, it will play just as well as a Yamaha 300 or 400 series flute.

You could try the Armstrong, but they don't have the reputation that Jupiter, Pearl or Yamaha have for modern scale and a headjoint designed for advancing tone development (in other words, suitable as step-up flutes). I haven't heard any fantastic reviews of any Armstrong except a) they were very sturdy student flutes back in the 80s when I was in Jr High, and there was an Armstrong 'Heritage' (I think) handmade by Jack Moore, if I remember correctly, that were fantastic but are quite rare.

What Patrick said is a good idea -- try all of them out (and hey, blindfolded -- I like that idea). You won't know they best suit you until you try.