What we like the most is its completeness: Wialon has several modules, beyond the regular tracking, that serve very specific purposes (maintenance, routes, eco-driving, and so on…); and if your end-customer or your company needs something else, that special touch, we’ve found the development tools very helpful for that purpose.
I would define Wialon as a Minotaur in a good way. It has the strength and power you look for in a software, and also that very human and personal touch of it’s flexibility and of course, Gurtam’s team and community. Cons: Least? No idea how to answer this questions. Flaws are minimum (99.9% uptime), and some UX details that you easily get used to.
Bottom line, we love it.