The CR-3 is not expensive and does the job really well. The very small one needed glasses to read it! Not used the other specifically, but they look to be exactly the same.
If you intend to take your exams in UK, the CR-3 is the only one of the two mentioned that is allowed in the exams.
There used to be a large workbook for the Jep, but it's hard to get these days. Since you can't take PMs, here is a link to a new version -
Pilot Training & Ground Studies - Electrocution's Aviation Books.
Phil