I'm a n00b, so take my ramblings for what they cost you, BUT, I bought my p229 DAK because:
1. My other gun is a S&W 642 (DAO), and I like the idea of the similarity (trigger, safeties)
2. Same trigger pull (sorta) every time for consistency and simplicity
3. No decocker for me means simplicity, one less thing to forget
4. No SA might decrease the odds of a "hair trigger" claim by a retarded DA
I love it. Now that I've taken it to the range 4-5 times, #2 in the list is why I would buy DAK again.