There are four basic types of mount structures:
Roof mount structures typically keep the wire run distances between the solar array and battery bank to a minimum, which is good. But they also require roof penetrations in multiple locations (a potential source of leakage) and they require expensive ground fault protection (GFP) (a requirement in article 690-5 of the National Electrical Code).
Ground mounted solar arrays do not require GFP but they do require fairly precise foundation setup and are more susceptible to vandalism and excessive snow accumulation at the bottom of the array.
Pole-top mounts are relatively easy to install. After squarely securing a pole (steal or treated wood etc.) into the ground, the solar modules are mounted and racked on top of the pole. Pole-top mounts are a better choice for cold climates because snow slides off easily however they may be hard to clean.
Pole-side mounts are easy to install, are typically used for small numbers of solar modules (1-4) for remote lighting systems where an pole exists to attach them to.
Trackers increase the daily number of full sun hours and are used for solar water pumping applications. Trackers are extremely effective in the summer time when water is needed the most. In northern climates (or zones further away from the equator), typical home energy usage peaks in the winter when a tracker mount will make very little difference. A less expensive fixed roof, ground or pole-top mount with more modules will perform better in the winter than fewer modules on a tracker. However, in southern climates (or areas closer to the equator) your energy usage peaks in the summer and a tracker system may be the better solution.