Q:

Is hibernation still dangerous?

My laptop hardware supposedly has good hibernation support for Linux, but I have heard too many horror stories about hibernation. Have things changed or is it still a really bad idea to hibernate?

A:

Hibernation has worked flawlessly on every laptop I've had for the past six years or so.  The only "horror stories" I've heard in recent times are people running development versions of distros (mostly Ubuntu people) and those running really oddball hardware (like laptops from "Shenzhen People's Laptop Factory #4" which have video cards with manufacturer IDs that lspci's never heard of).

A:

I use hibernation continuously for 5 years in both my laptop and my desktops. It is a primary requirement for me, since I like to leave many applications open (specially my IDE with my currently working projects, usually while doing something that demand some hard brain warm-up to get into it again after a long pause... if I leave the application windows open, with the editor in the very line I stopped the previous day, the brain warm-up is much faster when I get back).
Hibernation support have been getting better and better every day. My home desktop is quite peculiar (64-bit, nVidia proprietary drivers, Xinerama support enabled with two screens, KDE4 Kwin composite enabled (compiz-like), VirtuaBox VM running a WinXP, an external USB HDD, etc), and everything goes and comes back without any major issue.
Just some notes:

The system has to be turned back on with the same state it was when shutdown. This is specially important in my case because of the external USB HDD. Sometimes I forget to switch it back on when I resume from hibernation, and as it is expected, it is forcibly umounted and applications using it break.
Be careful with dual boot. Fedora had a really nice feature that it bypassed GRUB whenever the system was in hibernating state, jumping directly to the previously selected kernel and then proceeding with system wakeup. Now I'm using Ubuntu, and it doesn't do the same. After power on, you get to GRUB and can select a different kernel or a different operating system. I had some disastrous experience due to this. I had my NTFS partition mounted on the laptop before hibernation, and then inadvertently went to WindowsXP while Linux was hibernating. When I got back to Linux, I had this delicate situation. Ubuntu really needs to improve here, like in Fedora.
Own experience: avoid ATI video cards at all costs. Their proprietary drivers suck too hard, hibernation was major disaster. I don't know if anything changed in the last years. Intel (open-source) and nVidia (proprietary) work great.
Although I keep a VirtualBoxVM running, I usually do a live snapshot and close it before hibernating because this reduces overall system memory usage and hibernation/resume cycle is faster.

Small issues:

I use the w83627ehf/atk0110 driver to control the internal fan speeds. PWM outputs are not saved upon hibernation, and come back at full speed. You just need to set their speeds again after resume, simple.

