I've been using Django for 10 years, and I never experienced an ORM bug, and when it couldn't do some complicated join, I just did a raw query. For everything else, it saved me tons of time.
Funny. In my experience it's been the difference between working on the problem, and working on 12 different files each full of several page-long functions (either containing raw SQL strings, or string fragments to be assembled based on arguments passed in).
Then, out of the 6 months you save by not-doing-that, you spend about 6 days dealing with bad performance, ORM bugs and limitations, and like matters. (And the bad-performance areas are the ideal place to put in your choice of raw SQL.)
But your project may have different needs. Depends on how many tables you're managing and how many different ways you need them and how easy you need the "get me a test object for my integration test" to be.