Been using the 64 bit version since it was first released and I've had no problems "researching" various flash games.
I used nspluginwrapper before that but it was annoying always having to pkill npview.bin when it was hogging the sound device.
YMMV I guess. I *only* use flash for streaming video, so I disable all plugins in Opera and only enable them for sites like youtube. Anything of high-ish quality and longer than 10minutes usually stutters and does weird things like suddenly jumping out of fullscreen mode and refusing to go back into it.
And before the Firefox mafia strikes: not only does Opera use the Firefox plugins, but the ghastly stuttering and lagging of videos is the same in both browsers.
Bring on HTML 5, say I...