Pro's
- Highly efficient
- Implementable on a large scale
- Good for ISPs - anything with multiple connections to many hosts
- Prevents loops when there are multiple physical links
- Load balances over redundant links
Con's
- Not stable
- No digital identifiers - implicit trust between routers running BGP
- If misconfigured, chaos can ensue by advertising itself as the best path to an unrelated network
- AS's advertising each other's paths may lead to repeated advertising - possibly a loop
- There are very few alternatives in use. An example is GNU Zebra Routing.