Hard to say. Now that we switched to PostgreSQL, operations run much more smoother. You literally can't compare it. But this is also attributed to the major refactoring we did under the hood too; as I pointed out in the article, I simply "driver switch" didn't cut it :-)

We hit the max connections limit in postgres too at peak times (but no lock-up or similar thing happened) and per advice of our hosting provider we added pgbouncer to the stack last week and will hopefully don't have much problems here anymore.

Disclaimer: I wrote that article.