When comparing ii vs Quassel, the Slant community recommends Quassel for most people. In the question“What are the best IRC clients for UNIX-like systems?” Quassel is ranked 4th while ii is ranked 9th. The most important reason people chose Quassel is:
Quassal is available for free with source code licensed under GPL and available [here](http://bugs.quassel-irc.org/projects/quassel-irc/repository).
Specs
Ranked in these QuestionsQuestion Ranking
Pros
Pro Everything is a file
ii is a minimalist FIFO and filesystem-based IRC client. It creates an irc directory tree with server, channel and nick name directories. In every directory a FIFO in file and a normal out file is created.
The in file is used to communicate with the servers and the out files contain the server messages. For every channel and every nick name there are related in and out files created. This allows IRC communication from command line and adheres to the Unix philosophy.
Pro Free and open source
Quassal is available for free with source code licensed under GPL and available here.
Pro Distributed
It's possible for a front-end client or multiple front-end clients to connect to a single core client. This allows setting up an always on-line core that can be accessed from anywhere.
Pro Easy installation on Ubuntu due to the existence of PPA's
Right now Quassel has a PPA maintainer, which allows you to install the stable version or daily versions.
Support for PostgreSQL as database backend and easy to configure for people that know a bit about systems.
Cons
Con Potential memory bloat in monolithic client if left running for a period of time
(I don't know if this problem has been fixed in recent years, but I have doubts)
Con No DCC support
DCC or Direct Client-to-Client protocol allows for private communications between users (without the traffic being routed through servers). Neither chat nor file transfers are supported.