I need a commenting system for a site I am working on. It needs to be able to be polymorphic so it can support different types of models that need comments. What would be the smarter thing to do (less code, complexity, and effort required): use Disqus, create my own system, or use some other commenting system (if you know any others please tell me)? Any advice on this topic would be much appreciated. Thanks!
Disclaimer up-front: I haven't used Disqus but they seem to be the best combination of power and effort for your needs, which are relatively straightforward. Because they are a dedicated and competent firm (and used by millions of sites) you are likely to have more features, support, and easy upgrades than if you were to build on your own.
I might have suggested a custom-built solution if your requirements were unusual in any way, but they seem to be typical for a modern commercial site. Good luck!