In the case of firefox, it basically makes it less stable than a nightly build considering how often it crashes, and subtly breaks screen sharing in weird non-obvious ways. This experience has me guessing that Canonical probably cares more about server Ubuntu now than it does about desktop Ubuntu, which is a real shame.
While there are workarounds, I specifically endorsed Ubuntu in the first place to many people because these kinds of workarounds used to not be necessary. It's a real bummer honestly, not sure what else to recommend in this category either.