+* Ability to know :ref:`exact decoded <decoding>` objects offsets and
+ lengths inside the binary
+* Automatic decoding of :ref:`DEFINED BY <definedby>` fields
+* Ability to know exact decoded field presence, emptiness: for example
+ ``SEQUENCE`` can lack ``OPTIONAL SEQUENCE OF`` field, but also can
+ have it with no elements inside
+* **Strict** DER-encoding checks. If whole input binary is parsed, then
+ it must be completely valid DER-encoded structure
+* Ability to allow BER-encoded data with knowing if any of specified
+ field has either DER or BER encoding (or possibly indefinite-length
+ encoding). For example
+ `CMS <https://en.wikipedia.org/wiki/Cryptographic_Message_Syntax>`__
+ structures allow BER encoding for the whole message, except for
+ ``SignedAttributes`` -- you can easily verify your CMS satisfies that
+ requirement
+* Ability to use mmap-ed files, memoryviews, iterators, 2-pass DER
+ encoding mode and CER encoder dealing with the writer, giving ability
+ to create huge ASN.1 encoded files with very little memory footprint
+* Ability to decode files in event generation mode, without the need to
+ keep all the data and decoded structures (that takes huge quantity of
+ memory in all known ASN.1 libraries) in the memory
+* ``__slots__``, ``copy.copy()`` friendliness
+* Workability with ``pickle``
+* `Cython <https://cython.org/>`__ compatibility
+* Extensive and comprehensive
+ `hypothesis <https://hypothesis.readthedocs.io/en/master/>`__
+ driven tests coverage. It also has been fuzzed with
+ `python-afl <http://jwilk.net/software/python-afl>`__