I'm not familiar with either of those, but I can tell you my Yami 584 plays like a dream compared to my old Armstrong 80. The Armstrong's a good solid flute, esp since my repairman tweaked it to make it more responsive. And I use it for rehearsals and practicing and most concerts outside. When I switch to my Yami the last week before a solo, runs just fly! Low notes pour out. My fingers feel the vibration of the notes. That high E sings even without the split-key.
If you can afford it, then yes. Spring for the Yami. But keep your old flute as your workhorse.
1975 Gemeinhardt M2 in chrome nickel
1982 Armstrong 80
2006 Yamaha 584
1978 Artley piece of crap 15 P
1982 Gemeinhardt 4S
1980s (?) Armstrong all wood (no model)
2006 Jupiter di Medici G0199
Plus many many flute-cousins....