Pick one that is the easiest to follow. I am all for the do not use frameworks and stuff but there is a lot to learn from them. Yes, eventually you should write your own or develop a system that you can pick up and not reinvent the wheel every time you start a new project.
I avoided all these systems till I gave bootstrap a go - that too was way too bloated for my taste but I persevered and learned and in the process I sort of developed a grid boilerplate so to speak that when I start a new project, I have my basic CSS written out and am not writing float:left's and clear floats and widths etc for each new project.
So bottom line is, pick an easy one, sift out the crap work on your own. The trick is to keep it simple, readable and reusable.