What do you look for in a pre workout

Hi guys,

I'm sure you all have a wealth of knowledge and I would like to tap into that.

As members of this site I was hoping you could help?

I would like to know what you all look for in a pre work out.

I'm sure your answers will be varied but I would like to know why you look for what you do and possibly a little bit about yourself too.

Any help would be great.

Class this as market research if you will ...appreciate the help everyone.