Those are some good reasons. I like the way disambiguation is done, however it's aesthetically annoying. It feels like I'm using a search engine made by Fisher Price. For me to switch from Google would require a cleaner interface.
I find the "infinite" scrolling kind of annoying. It's jumpy when it loads and it gives you no reference of where you are in the results (versus which page you're on with Google, for example).
Thanks, I've been seeing references to DuckDuckGo for the past few months, but I'm going to try using exclusively this for the next week and see how it works out :P