Acctually I wanted to give my opnion on these, especially just having come from an all day seminar with her. These rulers are amazing. Now I'm not sure that you need ALL of them, however using these rules with her Smart Piecing techniques will save you alot of time and money.
Also the kit comes with her Smart Piecing DVD, if you have never seen Kaye...she is a RIOT! And her DVDs are very informative but best of all entertaining.
I would simply say to research them and then make a decision that works for you. After trying them I have about 6 of the different rulers and think they are worth the money.
So that's jsut my 2 cents on the whole thing.