To the OP: I had been looking forward to the release of the Centrotec Set the minute I purchased my T15 this past January. I knew the price was going to be high, but it's the number of stuff I know I won't use that has convinced me not to buy the set. Instead, I have purchased the items I know I will use right now and I will be awaiting for the new items that I can purchase individually. I did purchase the Twinbox because it has one of each bit. I think the Twinbox is a wonderful idea for the hobbyist. I don't know about you, but it takes me a long time to eat through my bits.
So with the money I believe I have saved by purchasing the items I definitely know I'll use, I will then role the extra money towards a CXS or C12. I want to try both drills side-by-side prior to making a decision. My local dealer has promised to give me a ring the minute they have a C12 in house.
Good luck with you decision, but think of all the other wonderful Festool items you can purchase if you don't buy the Centrotec Set.