Ask HN: What is a good C++ unit test framework for a startup?

Don't have a ton of code or test cases yet - just three months into a startup with four developers.

Looking for something relatively lightweight, with a small learning curve, that can keep us honest for the next year or two. I've used CppUnit in the past. Didn't hate it. Wondering if there's something better.

Do you have opinions on this? Looking for your war stories, whether good, bad, or plain ugly.