If your the only user on the gOS computer or your default login is USER then I would recommend the Hibernate function as apposed to shutting every thing down. It saves power and makes startup much quicker.
Both Hibernate and Suspend have worked all but one time for me that's not bad when my Mother got her new Macintosh* it had a glitch in OS X 'sleep mode' and would not wake up or it would wake up but not go back on line. I am using Hibernate every time I go to bed and every time I go to work that works out to be about twice a day. I don't have much to compare it to at work our computers are just on or off and my other computers are running BOINC (SETI@home and Malariacontrol.net) , so they are on all the time. At work I use use Puppy Linux a liveCD so it is only on when I use the computer.
Next is Suspend it is used the most on this gOS computer, If say for example I go have lunch or I go to watch a little TV because I know the minuet I get back I want the computer up and running so I can check my email or head over to Makezine.com.
*This was a long time ago and the problem has been long since fixed (by Apple).