It's hard to answer this question. It is heavily dependent on how you like to learn the product. Some people do not read the manual cover to cover and only refer to sections as a reference or use the .PDF version to perform quick searches for specific phrases.
Even if you like to read the manual cover to cover, then the .PDF is available for that. I have had Legacy for some time and have purchase two of the printed manuals during version upgrades. Honestly, I have not really used them that much (they both still look brand new).
As far as the training CD's ... I have no experience with them to have an opinion. I can only say that I've had good luck with the product even without the training videos. There are many freely available Webinars (online videos) from the website.
How you use the program can be a personal decision. The biggest problem that I've had is entering a type of data one way and later deciding to add it in a different way ... but, that comes from entering many records of the same type and deciding I like to capture details differently.
The Legacy program is freely available with a lot of it's functionality. I would suggest you download it and play with it for a little while. This will tell you if you like the product and it will also give you an idea if you need the additional training CD.