Where should I put new SSD (for OS X)? Optibay? Why?

See this article about drive locations & reasons.

Some old stuff here Machead - I have over 40 MacBook Pro's with SSD's in the optical drive carrier (we have mostly SATA II SSD's but a few SATA III on the newer MBP's). I have ML on these systems with the latest EFI firmware. I also disable the hibernation services as well. We don't have freezing or beach ball issues.

I should point out we do the reverse on the older PATA optical drive MBP systems. Putting the HD in the optical drive spot. We did notice the HD's didn't do as well after they where moved. As we were planning on upgrading them any ways at the end of the fiscal year a few years ago we didn't bother fixing them. Most of the staff work on site in trailers or offices so they aren't bouncing the systems when they are running. Which could explain why we didn't have that many failures.

I have heard that some of the HD's had no motion sensors ( a reason not to put them in optibays). Explaining the "disable hibernation" step would probably be beneficial. As well as disabling/unchecking/changing "put the HD to sleep when able" setting. No one mentions shorter battery life...but probably not as bad running an SSD and an HD, or two SSDs compared to two HDs. It's all a mater of trade offs, and, to some extent trying to have a laptop stand in for what a desktop wold normally accomplish.