Thru-the-glass antennas do not work well and the Little Wil is a good magnet mount antenna.
Wilson makes some of the best overall CB antennas on the market, so any of their antennas will work fine, both their fiberglass and their metal shaft antennas.
A magnet mounted antenna usually has a good ground path to establish the ground plane necessary for good communications. Mounting an antenna any other way will require a ground between the antenna mount and the body/frame of the vehicle.
Main things to remember get a good quality antenna, next get good quality coax, then think about the CB.
luck,