Some aspects might depend on "where" in Santiago you are going. Metro only has one stop and Caribe Tours has two depots in Santiago-one on either side of town-so where you have to go to do your business might influence your choice of bus line.
Also, taxis are inexpensive in Santiago, $100 to most places. However, the taxis that work the bus depots want more.
If you know when you are coming you could get in touch with JJ over at
Welcome To Paradise Transportation and reserve his services for the day..or for a few hours, and save some confusion and hassles.
Otherwise call Apollo taxi or EmiTaxi, and they'll pick you up at the station.
HB