I like Python3. They fixed all the inconsistencies in the language.

Sucks that some people are still stuck with 2.7 but it's definitely worth upgrading if you can.

Lua does it very frequently, and people generally don't get quite as upset about it. The popular LuaJIT compiler and interpreter even implements a language that is somewhere between Lua 5.1 or Lua 5.2 without matching either exactly.

I don't think that developers hated Python 3. They hated to having to rewrite/fix a ton of 3. party modules. For a long time the improvements in Python 3 simply wasn't worth the hassle of dealing with incompatibilities.