I have just downloaded the Bryce 5.5 $20 offer from DAZ having previously downloaded the free Ver 5 from the DAZ website - both are the Apple Mac versions. I have carefully been through the contents of all the presets, skies etc and have found that there are some new items in 5.5, some overlap between the two, but a lot of stuff from ver 5 that is not in the ver 5.5 download.  This is most likely due to a compromise between new features, and manageble download sizes and bandwidth usage for DAZ.

I would advise people to go through the exercise of comparing the contents of both packages rather than just trashing ver 5...  i.e. you will end up with more terrain maps, light gels, sky presets, and some materials, and the preset scene examples...  I am sure that the old ver 4 two CD set will also have a heap of content which is unique and still useful for ver 5.5.  

Interestingly, I have found that using the o/s for moving stuff into the Bryce Objects folder even when the application is running will still make those new object sub-folders and files available when the Create>Objects popup is opened. This applies to Mac, not sure about the Windows version.