PfR can inject temporary static routes. You need to redistribute them across a routing protocol (one known only to the border routers works well).
Main advantages, it's "free" and besides link load balancing, it can adjust for end-to-end performance.
Main disadvantage, it places additional demand on your routers. (Although depending on PfR's configuration, dealing with full Internet BGP, I've seen, adds more load than PfR.)
