I&#x27;ve used (tested) Python3 many times over the years and releases. I&#x27;d consider the changes trivial. I&#x27;m not anti-Python3, I&#x27;m pro-PyPy4.<p>In my attempts to test Python3 releases though I&#x27;ve ran across bugs and performance regressions from 2.x. After I continually ran into this in a few releases I eventually threw my hands up. The last release I ran tests on was 3.4 and I&#x27;m no longer interested in later releases until something as substantial as PyPy&#x27;s CPU performance and removal of the GIL (PyPySTM) shows up to beat what I have now.<p>It&#x27;s slick to have the entire Python2 ecosystem, major performance boost to your code, and still leave the door open for Python3 if they ever stop bloating the language.<p>Other than being dramatically slower than PyPy4, Python3 is also feature soup. I strongly dislike technical churn rather than true technical innovation (which is what PyPy represents). I&#x27;m more in line philosophically with Go, I&#x27;d prefer to remove features until you&#x27;re down to a very concise and stable core. Python3 has many negatives, but from my perspective they keep piling on more.