Unfortunately sleep and hibernation modes depend on many factors: how the hardware works, how the PC hardware systems interact with each other, how ugly the device drivers are written and in rare cases - which software did you run (yes, Windows isn't a 100% fortress and can make the PC to run wrong after some software has been started).
Usually problems arise in desktop PCs as they have components from different vendors. Laptops usually have finely tuned components that fit each other. But even there no guarantee could be given.
Here is my experience:
I encountered full Windows destruction after a PC went a couple of time to hibernate mode: some of drivers supposedly couldn't correctly recover their state that must correspond to current hardware state; memory had been corrupted and it affected in some way important system data. Then this data had been written to disk and Windows was finished.
One of laptops has been used in battery backed sleep mode. It was put in sleep mode for a couple times each day and finally Windows Vista began to encounter strange errors and worked decently only without paging file. The final moment of all this was that Windows initiated chkdsk and hung at every boot on phase 5. I replaced the HDD, cloned the system and everything repeated again: after a year the system went to unusable state.
My wife's laptop sometimes refuses to wake up from sleep. All it shows is a black screen and high fan speed.
There are plenty of problems related to sleep modes. On every PC it is a lottery with 40% of winning chance.
So my advise is to put up with it and disable the hibernation mode.