On the rarely computer I chose stand by option and all that did was to turn the screen blank than display the sign on screen with the password box. So there is not any stand by option that really works for that computer.
Yes, turn it off. I see what makes sense to do that, actually, as long as there's no reason to leave it open. Besides, it's nice to see it start fast with the SSD. And if it's Windows, sometimes even doing that is better for it's health.
If it will be weeks or even days before you use a computer again then it makes sense to turn it off.
I have 2 computers that I leave on all the time. One is my media server, it gets used off and on all the time so it's not practical to turn it off since I can't predict when someone in the house will want to watch something from it. The other is my main computer which I use everyday, multiple times per day so leave the computer on and just let the display blank in between uses.
I have several other computers that I use here and there, those are turned off when I'm done using them since I don't know when I might use them again.