Status: 4.x branch Suspended development; 5.x branch active development.
Pros: An attractive interface out of the box; a decent number of high quality extras; compatible with a number of different protocols.
Cons: Currently suspended in time. You can download it, but you won't see any progress on it for a few months yet. On top of this, extras are down; you'll have to do with what extras come bundled with it. MSN no longer works in it.
Review: Back in it's hey-day, Proteus was the king of instant messaging clients for the Mac. That's right, it was the best. Then one day, the creator was head-hunted by Apple and development fell into the hands of a company named DefaultWare. Sadly this spelt disaster, as development slowed to a snail's pace and releases became few and far between. Developers left the project and eventually DefaultWare folded, leaving the app to fall into the hands of some volunteers, including myself. Note that if there was anything DefaultWare did that was popular it was turning Proteus from a shareware app to a free app. For a while we were able to cough up support from various developers, but long term committals were few and far between. Recently money has been funnelled into Proteus development in the hope of stimulating development but sadly it will be a while before a solid release is made. The current version is 4.2.1. and development of the 4.x branch has been dropped in lieu of Proteus 5, the next generation of instant messaging clients - it could be huge when it’s released and should also be available for iPhone, iTouch and perhaps even iPad. We’re also working on getting our extras back online in order of preference set when last online and judged by the public.