Thank you for the answer.
What I wanted to know was whether CHDK works in the same way on all supported cameras.
As waterwingz said, CHDK pretty much does, but the
pretty much can be important.
Obviously, some features depend on particular hardware or features in the Canon firmware. This isn't clearly written down anywhere, so if you need a particular feature, you'll have to do some research.
There's another, less obvious factor too:
Ports are made and tested by people who actually have the camera, not some central team of CHDK experts. Frequently, the people who do this have never used CHDK before. This means that which features are tested and how well they are tested varies a lot, and the anyone who doesn't have the specific camera probably won't know. As developers, we can't just look at port and know whether everything works correctly.
If you want to do some research before purchasing, your best bet is probably to make a shortlist of supported cameras you'd be interested in (by price, form factor, zoom range etc) and then look at the wiki page and development threads for those model. You should also check reviews of those models: if a camera has poor image quality or bad performance, CHDK won't fix that. Generally, a camera that is better without CHDK will also be better with CHDK.
