[morelisp]

It is easy to look at Python 3.x today and say the migration should have been easy, but some of us were there, and remember how intransigent some core devs were about things like u"" and %, and how Python 3 offered nothing better upon release.

https://news.ycombinator.com/item?id=22036773

[TylerE]

Not to mention, as the cherry on the turd sandwich, performance of early 3.x versions was substantially worse than 2.7.

[_0w8t]

And it is still slower for small glue scripts. On my Windows 10 box hello, world script finishes with Python2 in 73 microseconds (the best time of 5 runs) versus 238 ms for Python3. That translates into noticeable slowdown of compilation time for a project extensively using python code in the build system.