I'm busily studying for the next MCPD upgrade exam: 70-552. I took 70-551 last week.
Now you don't have to take both (one is for Web and one is for Windows Forms developer)... but since they are free I figured “why not?”
And since the questions on both exams overlap, taking 70-551 actually gives me an advantage for the exam tomorrow. I have seen 1/3 of the questions before.
So if I didn't pass 70551 (or barely passed it), I should have a better score on this one.