The big difference between cinepaint and the gimp is cinepaint's deep paint ability, gimp is limited to 8-bit color channels, while cinepaint supports 8, 16, and 32 bit color channels.  This allows a photographer to stay within the 16-bit color range that is supported by most cameras and printers without destroying color information.

Edit mode does NOT do the UV Unwrapping - I know I unwrap UV's on Everything I make now - that is done on the UV Face Select mode -
As for the documentation not be as up to date as it should be well - it can't be an easy thing to keep up on the documentation of such a large project as Blender has become - remember it now does more than just '3d rendering' it has a game engine built in...

UV Face Select Mode was merged with Edit mode (I'm using 245.15 to have access to tangent space normals) 

The problem with flash memory as a storage device is that no matter which brand you use it will eventually go bad, so the best storage media would be something external to the camera that isn't prone to loosing data after a certain number of read/writes, CD-R/DVD+/-R, etc..

I know the documentation is available online, the problem is it is often outdated.  Probably the best example are all of the wiki's that still reference the UV Face Select view mode (note:  the specific mode that was available from the drop down menu that includes edit mode, object mode, etc.) which was removed in 2.44 IIRC in favor of using edit mode to unwrap the UV's.  For a complete newbie to 3d modelling or anyone that has experience with any of the commercial tools that lack of updated documentation is a major drawback.

Out of curiosity, what are the differences between a Windows build and a Linux build?

The only thing I dislike about Cinepaint is that the Debian Maintainer seems to have abandoned it, the Debian version is stuck at 0.20 with several broken image plugins.  Thankfully, this is free software and the broken plugins work perfectly compiled from source

I rated it fair because of the UI, the lack of updated documentation, and its plugin API breaking at each new release (ok, so that's really a python issue  ).  If there were official documentation that kept pace with development, the UI issue were fixed, and the plugin API was stable its rating would go up.