- Python 2.7 is the final Python 2.x release. Python 3.x is the future. The Python ecosystem needs to consolidate. A split or schism between different incompatible versions is not healthy for growing the community.
- Function annotations
- Decimal module 100x faster. As fast as floats.
- Easier to learn. (Less cruft in language and stdlib, more consistency, better docstrings, etc.)
- Much safer handling of unicode text and encodings: fewer bugs.
- More memory efficiency (shared dict keys (PEP 412) and space-efficient Unicode representation (PEP 393))
- Exception chaining
- SSL contexts in http.client