RPP  Without unlock code it will use 2 cores for conversion, with unlock code it will use all available. It may look like it uses more cores without the code though because Mac OS uses them for it's own needs to display progress bars and other UI elements of RPP. This is nice, but doesn't make conversion significantly faster.

Sorry for late answer - I've just noticed the question. I'd recommend to ask questions like this in email or in RPP support forum for faster turnaround.  
(Version 3.9.8)

RPP  Categorize it any way you want.

All features which were available in free versions are still free and all conversion related features also available for free, including support for new cameras and new conversion methods. Donation unlocks only some workflow helpers and support for more than 2 CPU cores on Mac Pro and Quad Powermacs. Size of donation is not limited in any way, including 0.00, i.e. not required - I send unlock key with no questions to anybody who have difficulties with donating and asks for it in email.  
(Version 3.8.4)

RPP  JPG files are not raw and there is not a single reason to open them with RPP, even though I admit this kind of things should be handled gracefully and I will fix this. Regarding crash on saving - please use support forum or contact me directly (details are on RPP web page), I'm certainly interested in fixing this kind of things.  
(Version 3.5.4)

RPP  You may use it without Photoshop, but main idea behind this applications is conversion quality and most likely you will need additional tools like Photoshop to at least apply some unsharp mask.

Give it a try If for some reason you don't like conversion quality of existing RAW converters, you want to squeeze everything out of your RAW files, you want to process some heavily underexposed images and see those details in shadows instead of black digital void or you just missing that old slide film look in your digital camera.  
(Version 3.4.6)