I feel like a broken record here but even with much better hardware, F360 is still unstable in OS X (though to be fair, I'm using 10.10 beta 3 so that could be a contributing factor).
Hi Scott,
i can fairly say 10.10 is not a problem. I used 10.9.4 until yesterday and then updated to 10.10 DP3 after having everything run on my MacBook Air for quite some while and yes, you're right unfortunately stability still is an issue though it isn't as big as it already has been. But that hasn't really changed between 10.9.4 and 10.10 - i had crashes during the last days on both about equally often.
Also performance is sometimes really not what you would like it to have on a 3,4GHz i7 with 32gb RAM and a gtx680mx with 2gb - you can't really have anymore besides a mac pro currently so i would expect some more power in Fusion with this hardware. On my older iMac that's running down in the workshop Fusion is really hard to use. I only open it for small corrections there when i need to repeat a 3d print or prior to some wood routing job but it's no real fun.