What Hack sucks:

• O(n) memory usage as Request / Respond body is in bytestring
• URL related parts are in String, so it's not completely optimized
• Unlike Rack and WSGI, it's not dynamic, so no object injection can be made to the Env hash

Hack is not a high tech product, as it was originally made for this stupid blog; It does, however, offers a choice: a lightweight approach to web programming.