I'm just one opinion, but I've flown both the wind 50 and the Osiris and prefer the Osiris... and I'm also flying a 2m Wind S Pro which is awesome.  The Osiris snaps more aggressively and seems to have better rolling/knife edge characteristics.    Flys great on a 5s setup, but you'll need to use a 16x10 prop to get true pattern unlimited verticals.  That set up will limit you to 5.5 - 6min flights.  The 6s setup provides longer flight times, but like you, I prefer just having 5s packs that I can also use in my 10s 2M planes.