I really love elementary OS, but there is a really annoying bug where the mouse shakes when I use my track pad. It's not a defective track pad, I have installed Ubuntu Mate and had no problems with the mouse.
I've had problems with my trackpad as well and posted my solution on reddit which you can check here: Link to Reddit. Not sure if it will solve your problem though!
Basically the command I've used looks like this:
sudo apt-get install xserver-xorg-core xserver-xorg-input-all xserver-xorg-input-evdev xserver-xorg-input-synaptics
all at once and not split by a new line.