How good is Yosemite - Is it worth to upgrade now or wait till it stabilizes I have iMac (2012) with OSX 10.9.5 (Mavericks) currently on it. I am a iOS app developer and need my mac best performing and can't let my mac go down for even 2-3 days.

I have read news about issues on Yosemite release and even some on iCloud bundled in the same. I wanted to confirm that is it stable enough to retain my work and performance of my mac as it is now.

waiting to reply from Maverick users.

EDIT for more clarifications :

I wanted more reviews specially on following sections from Mac / iOS Devloper Perspective


Stability 
Performance
Ease of Upgrade (as it is >5GB and available on Mac App Store only, in low bandwidth intennet it may get disconnected between download)
Recommended features e.g security updates


-- Vishal
There are some bugs as in every .0 release, but your mileage may vary as to which ones (if any) end up affecting you. Unfortunately nobody can predict that. If you are concerned about a critical production system being put out of commission, it is probably best to wait for 10.10.1.