The best applications for analyzing paths, that I've seen, have been in-house development projects. So, admittedly, I don't have much experience with commercial products for route optimization. Projects I've seen that analyze "best" paths to Internet destinations via multiple ISPs add instrumentation to content-serving applications to log stream performance details to a database or log collection system along with a timestamp. Another database keeps a periodic log of RIB data that lists the specific next-hops out of the AS. Another log keeps a running log of UPDATEs.
From joining up all of this information, you can figure out the ISP you're taking to a destination (at a given time) and how the stream performed. Then, add some logic to inject routes to try out different next-hop ISPs for some destinations.
Then, compare the newer ISP-path to the older one and see which performs "best". Where "best" means something specific to your application (optimizing for latency, cost, etc.) Cheers, jof