Ok, If I am understanding this correctly a Werebear character cannot be brought into the game until 4th level or higher. However as you have to have as many levels in a character class as a wearbear has HD that means you have to be at least 6th level before you can actually play one (this is according to the special rules for lycanthropes on page 23 of the DMG). As I understand it they are saying 6th level barbarian werebear = a 10th level barbarian. If you are using the the DMG rules, and because werebear is a template that means that you have a character that has the equivalent of a 6th level amount of xp (which is broken if you ask me). If you use the ECL method from the FRCS then the technical level of the character is 10.
Con is your most important stat, since you are going to be taking an HP hit for being 4 levels lower than everyone else, and that is important if you are going to be a front line fighter.
[edit: oops, gave the wrong page number]