I passed the 70-450 exam last week and completed the 70-432 exam earlier in April.
I have to say this certification is a much better test of your real world DBA skills then the MCDBA exams.
A lot less memorization required and a lot more critical thinking needed.
I started with Buck Woody's notes for the 70-432 exam and used the book he recommended.
There are no self-study kits for the 70-450 exam. I prepared for this exam by reviewing the exam's Skills Being Measured outline along with SQL Server Books Online.
For both exams, I will say that practical work experience does help a great deal especially with the 70-450 exam.
I answered a number of questions on the 70-450 exam just thinking about real world issues I have dealt with.
I will also say attendance at my local SQL User Group meetings, SQL Saturdays, Quest Software Virtual Events, 24 Hours of PASS, reading blogs, and twitter contributed to my MCITP success.
While it's always gratifying to earn the certification, I think the most valuable aspect of certification is that it pushes you to learn other parts of the product that you may not get a chance to use regularly.
Also, this success confirms for me the value of the social media, blogs, twitter, and community resources.
I don't think I would have passed the tests without using all of these resources.
Finally, I thank all of you who blogged about your certification experience while I was preparing for my exams.