Well i don't know "npm-check-updates" in detail, but this is one difference, yes. For us it is very important to know if and which module brakes the tests. In my opinion it doesn't it is no option just to update all dependencies without running the tests.
Based on npm outdated, updtr installs the latest version and runs npm test for each dependency. If the test succeeds, updtr saves the new version number to your package.json. If the test fails, however, updtr rolls back its changes.