When comparing Quassel vs Pidgin, the Slant community recommends Pidgin for most people. In the question“What are the best IRC clients for Windows?” Pidgin is ranked 4th while Quassel is ranked 7th. The most important reason people chose Pidgin is:
Pidgin not only supports IRC, it also supports plenty of other services such as AIM, Google Talk, MSN, ICQ and plenty of others. This way, you can have all of your conversations in the same app and won't have to deal with multiple chat windows being open.
Specs
Ranked in these QuestionsQuestion Ranking
Pros
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.
Pro Support for a wide range of additional chat services
Pidgin not only supports IRC, it also supports plenty of other services such as AIM, Google Talk, MSN, ICQ and plenty of others. This way, you can have all of your conversations in the same app and won't have to deal with multiple chat windows being open.
Pro Free and open source
Pidgin and its code is completely free and open source. Pidgin has no ads and no features behind a paywall.
Pro Cross platform
The Pidgin instant messaging client is cross platform, working on Linux, Windows and OSX.
Pro Convenient notification features
Like other quality IRC clients, Pidgin features notifications that the user can set in order to have a variety of things happen when the users is mentioned, such as an audio cue or changing the system tray icon.
Pro Highly customisable with plugins
Pidgin not only has a large plugin library built-in, but also an array of third party plugins for a variety of functions.
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.
Con Miserable IRC font controls (as of 2.13.0.17)
Does its best to avoid putting sensible default font controls in any place where you can get to it. And when it does grudgingly change it, based on system preferences (not local preferences), it does so in an inconsistent and unpredictable fashion.
Con No native VoIP support
While there are plugins there is no built in support for VoIP in Pidgin which is time consuming to implement instead of being baked in from the jump.