A decade or more ago solar panels were very expensive. Despite the cost (and maintenance, and extra points of failure) you could sometimes come out ahead with a tracer.
But the price of panels has dropped like a rock. (Something like Moore's law applies to their technology improvements.) Meanwhile the price of the mechanical stuff for a tracker has not fallen substantially (has perhaps risen?) and the cost of the components of its control electronics (where it's even used), though it may have dropped, hasn't dropped substantially.
So these days it makes more sense to just buy more panels and keep it cheap, simple, and reliable.
Nearly the only place I've seen pros installing trackers at all these days are in large solar arrays, such as those over parking lots, where rotating a single shaft can tilt a BUNCH of panels at once. Even there they're not tracking the sun in 2-D, just rotating on a parallel-to-the-ground axis. Such systems have gaps between the panels, and are limited in how far they can track before the next row of panels shades the current set. For a home system you'll probably be more pressed for space and will want to make the panels contiguous. So one big composite panel, facing equatorward and tilted up to your latitude (maybe +- a seasonal adjustment or just tilted up a bit extra to get more power in the winter when sunlight is weaker and more precious), or several east-west rows of them spaced so they don't shade each other even at the winter solstice, is what I'd suggest.
(I DID see one at an auto dealership. But it isn't a proper tracker - the panel, though it has two motorized joints, ends up at a fixed angle to a vertical axis rather than facing the sun. It looks to me like more of an advertising gimmick than a serious solar energy collector.)
