do you need motorized for timeplase and motion controlled shots
do you want it to work with different length tracks or not.
what are you looking to film with it? just skiing or other film projects.
here are the sliders ive used and really liked
Dana Dollys are my favorite non motorized because you can use it with normal speedrail so you can have different length and customize it a little more. It can also support large camera setups so if you ever need to use it on a larger project it will work with heavy camera builds.
Manfrotto Camera Slider 60 inch - its smaller and lighter weight than a dana dolly with speed rails and is cheaper but wont support as heavy of a camera. this would be the easiest to shoot with on the mountain or in the field because of the size and weight.
Kessler Second Shooter. Its great for repeating moves and motion timelapse. It seemed pretty durable for a motorized slider and its pretty quick and easy to set up and program moves.
I would suggest an Edelkrone SliderPLUS they vary in length and price but they are pretty small and compact if that what you are looking for. It all depends on your needs, wants and price range but they go for about 400 to 700.