As pilots, we need to know what the weather is doing before we take off and once we're in the air. There are copious free weather sources while you're on the ground, but unless you have your own flight dispatch department supporting you from the ground there are really only two options once you're airborne.
By now you're probably aware that SiriusXM is a satellite based system that brings a lot of capabilities to the cockpit but for a price. The alternative is the ADS-B Flight Information System, which has some limitations but that is rapidly catching up in terms of capabilities.
Our comparison chart gives you an up-to-date comparison of the features and limitations of each solution since there have been a number of recent changes.